Paraves Sereno, 1997
Definition- (Passer domesticus <- Oviraptor philoceratops) (Holtz and Osmólska, 2004; modified from Sereno, 1998)
(Vultur gryphus <- Oviraptor philoceratops) (Cau, Beyrand, Voeten, Fernandez, Tafforeau, Stein, Barsbold, Tsogtbaatar, Currie and Godefroit, 2017)
= Troodontidae sensu Varricchio, 1997
Definition- (Troodon formosus, Saurornithoides mongoliensis, Borogovia gracilicrus, Sinornithoides youngi <- Ornithomimus velox, Oviraptor philoceratops)
= Paraves sensu Cau, Beyrand, Voeten, Fernandez, Tafforeau, Stein, Barsbold, Tsogtbaatar, Currie and Godefroit, 2017
Definition- (Vultur gryphus <- Oviraptor philoceratops)
Comments- Paraves as a concept can apply to any topology including Oviraptor and birds, but explicit topologies were rare until the 1990s. Kurzanov (1981) described Avimimus as closer to birds than known theropods, as also assumed by Chatterjee (1991), so would count as a paravian. Paul (1984) placed troodontids closer to birds than oviraptorosaurs, and in 1988 also placed avimimids there, positioning Archaeopteryx and dromaeosaurids more basal in both works. Similarly, Thulborn (1984) placed Archaeopteryx, tyrannosaurids, troodontids, ornithomimids and Avimimus closer to birds than Oviraptor, with dromaeosaurids more basal. Gauthier (1984, 1986) had a more modern arrangement where deinonychosaurs (including dromaeosaurids and troodontids) were closer to birds than caenagnathids (including Oviraptor) and elmisaurids. Holtz (1992, 1994) on the other hand only placed dromaeosaurids there, with troodontids closer to oviraptorids. Makovicky (1995) had a similar topology but with dromaeosaurids and Ornitholestes in what will be Paraves. Sereno (1997) first used Paraves as part of a node-stem triplet sister to Oviraptorosauria, but without explicitly stating its internal specifier. This was handled by Sereno (1998) who defined Paraves as "all maniraptorans closer to Neornithes than to Oviraptor." Holtz and Osmólska (2004) later added species-level specifiers. In the early 2000s with the discovery of bird-like basal troodontids like Sinovenator, troodontids were consistantly paravians while Avimimus and Ornitholestes were near universally excluded (25 and 29 steps to add in Hartman et al.'s 2019 matrix; they fall out as a scansoriopterygid and dromaeosaurid respectively). A heterodox exception is Maryanska et al.'s (2002; also independently recovered by Lu et al., 2002) hypothesis that oviraptorosaurs are closer to Aves than deinonychosaurs, so that not even Archaeopteryx is paravian, but this takes 12 more steps in Hartman et al. (2019). More recently, taxa which can controversially be paravians include alvarezsauroids (11 steps to add; which brings therizinosaurs as well), Fukuivenator (11 steps to add), Yixianosaurus (7 steps to remove), Protarchaeopteryx (3 steps to add; increased to 5 steps with added oviraptorosaurs) and scansoriopterygids (9 steps to remove).
Despite robust support for paravian monophyly, the interrelationship between troodontids, dromaeosaurids and birds remains contentious with recent studies alternatively favoring joining troodontids and dromaeosaurids as Deinonychosauria (Hartman et al., 2019; Hu et al., 2018; Lefèvre et al., 2017; Shen et al., 2017; Godefroit et al., 2013b; Senter et al., 2012; Turner, Makovicky & Norell, 2012), placing troodontids closer to Aves than dromaeosaurids (Gianechini et al., 2018; Cau et al., 2017; Foth and Rauhut, 2017; Lee et al., 2014; Foth et al., 2014; Godefroit et al., 2013a), or joining dromaeosaurids and avialans to form Eumaniraptora to the exclusion of troodontids (Agnolín & Novas, 2013). As first demonstrated by Xu et al. (2011) and Agnolín and Novas (2011), the consensus positions of archaeopterygids as birds and unenlagiines as dromaeosaurids can easily change with small adjustments to the TWiG matrix, making these clades active variables in paravian topology as well. Indeed, Hartman et al. recovered the topology used here as most parsimonious, but two alternatives were only one step longer. In one, troodontids, unenlagiids and archaeopterygids are successively closer to birds than dromaeosaurids. In another, unenlagiids pair with dromaeosaurids, and troodontids pair with archaeopterygids, all within Deinonychosauria. These should be considered basically equally likely pending further analyses.
References- Kurzanov, 1981. On the unusual theropods from Upper Cretaceous of Mongolia. In Resetov (ed.). Iskopaemye pozvonocnye Mongolii. Trudy, Sovmestnaa Sovetsko-Mongolskaa paleontologiceskaa ekspedicia. 15, 39-50.
Gauthier, 1984. A cladistic analysis of the higher systematic categories of the Diapsida. PhD thesis. University of California, Berkeley. 564 pp.
Paul, 1984. The archosaurs: A phylogenetic study. Third Symposium on Mesozoic Terrestrial Ecosystems, Short Papers. 175-180.
Thulborn, 1984. The avian relationships of Archaeopteryx, and the origin of birds. Zoological Journal of the Linnean Society. 82(1-2), 119-158.
Gauthier, 1986. Saurischian monophyly and the origin of birds. Memoirs of the Californian Academy of Sciences 8, 1-55.
Paul, 1988. Predatory Dinosaurs of the World. Simon & Schuster: New York 464 pp.
Chatterjee, 1991. Cranial anatomy and relationships of a new Triassic bird from Texas. Philosophical Transactions of the Royal Society of London Series B. 332(1265), 277-342.
Holtz, 1992. An unusual structure of the metatarsus of Theropoda (Archosauria: Dinosauria: Saurischia) of the Cretaceous. PhD thesis. Yale University. 347 pp.
Holtz, 1994. The phylogenetic position of the Tyrannosauridae: Implications for theropod systematics. Journal of Paleontology. 68(5), 1100-1117.
Makovicky, 1995. Phylogenetic aspects of the vertebral morphology of Coelurosauria (Dinosauria: Theropoda). Masters thesis, University of Copenhagen. 311 pp.
Sereno, 1997. The origin and evolution of dinosaurs. Annual Review of Earth and Planetary Sciences. 25, 435-489.
Varricchio, 1997. Troodontidae. In Currie and Padian (eds.). Encyclopedia of Dinosaurs. 749-754.
Sereno, 1998. A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen. 210(1), 41-83.
Lu, Dong, Azuma, Barsbold and Tomida, 2002. Oviraptorosaurs compared to birds. In Zhou and Zhang (eds.). Proceedings of'the 5th Symposium of the Society of Avian Paleontology and Evolution. 175-189.
Maryanska, Osmólska and Wolsan, 2002. Avialan status for Oviraptorosauria. Acta Palaeontologica Polonica. 47 (1), 97-116.
Holtz and Osmólska, 2004. Saurischia. In Weishampel, Dodson and Osmólska (eds). The Dinosauria Second Edition. University of California Press. 21-24.
Larson, 2009. Multivariate analyses of small theropod teeth and implications for paleoecological turnovers through time. Journal of Vertebrate Paleontology. 29(3), 132A.
Agnolín and Novas, 2011. Unenlagiid theropods: Are they members of the Dromaeosauridae (Theropoda, Maniraptora)? Anais da Academia Brasileira de Ciências. 83(1), 117-162.
Xu, You, Du and Han, 2011. An Archaeopteryx-like theropod from China and the origin of Avialae. Nature. 475, 465-470.
Senter, Kirkland, DeBlieux, Madsen and Toth, 2012. New dromaeosaurids (Dinosauria: Theropoda) from the Lower Cretaceous of Utah, and the evolution of the dromaeosaurid tail. PLoS ONE. 7(5), e36790.
Sorkin, 2012. Aerial ability in basal Deinonychosauria. Journal of Vertebrate Paleontology. Program and Abstracts 2012, 176-177.
Turner, Makovicky and Norell, 2012. A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American Museum of Natural History. 371, 1-206.
Agnolín and Novas, 2013. Avian ancestors: A review of the phylogenetic relationships of the theropods Unenlagiidae, Microraptoria, Anchiornis and Scansoriopterygidae. Springer Netherlands. 96 pp.
Godefroit, Cau, Hu, Escuillié, Wu and Dyke, 2013a. A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds. Nature. 498, 359-362.
Godefroit, Demuynck, Dyke, Hu, Escuillié and Claeys, 2013b. Reduced plumage and flight ability of a new Jurassic paravian theropod from China. Nature Communications. 4(1), 1394.
Brusatte, Lloyd, Wang and Norell, 2014. Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition. Current Biology. 24(20), 2386-2392.
Foth, Tischlinger and Rauhut, 2014. New specimen of Archaeopteryx provides insights into the evolution of pennaceous feathers. Nature. 511, 79-82.
Lee, Cau, Naish and Dyke, 2014. Sustained miniaturization and anatomical innovation in the dinosaurian ancestors of birds. Science. 345(6196), 562-566.
Lefèvre, Hu, Escuillié, Dyke and Godefroit, 2014. A new long-tailed basal bird from the Lower Cretaceous of north-eastern China. Biological Journal of the Linnean Society. 113, 790-804.
Cau, Beyrand, Voeten, Fernandez, Tafforeau, Stein, Barsbold, Tsogtbaatar, Currie and Godefroit, 2017. Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs. Nature. 552, 395-399.
Foth and Rauhut, 2017. Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs. BMC Evolutionary Biology. 17:236.
Shen, Lu, Liu, Kundrát, Brusatte and Gao, 2017. A new troodontid dinosaur from the Lower Cretaceous Yixian Formation of Liaoning Province, China. Acta Geologica Sinica. 91(3), 763-780.
Gianechini, Makovicky, Apesteguía and Cerda, 2018. Postcranial skeletal anatomy of the holotype and referred specimens of Buitreraptor gonzalezorum Makovicky, Apesteguía and Agnolín 2005 (Theropoda, Dromaeosauridae), from the Late Cretaceous of Patagonia. PeerJ. 6:e4558.
Hu, Clarke, Eliason, Qiu, Li, Shawkey, Zhao, D'Alba, Jiang and Xu, 2018. A bony-crested Jurassic dinosaur with evidence of iridescent plumage highlights complexity in early paravian evolution. Nature Communications. 9, 217.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Avepectora Paul, 2002
Definition- (majority of the distal edge of strongly anteriorly facing coracoids articulates with the anterior edge of a broad sternum at an angle of approximately 45-90 degrees from the midline as in Dromaeosaurus albertensis) (modified from Paul, 2002)
Comments- Paul (2002) named this to cover a similar clade to his 1988 Protoavia, identical in content to the consensus Maniraptoriformes. He cited Pelecanimimus' sternal complex as supporting ornithomimosaurs' inclusion, but eventual description of the postcrania suggests a more laterally oriented coracoid-sternal articulation. That being said, Hartman et al.'s 2019 topology resolves the strongly bent coracoid as being a paravian character convergent in derived oviarptorids, derived caenagnathids, Falcarius, Neimongosaurus, patagonykines and Archaeornithomimus.
Reference- Paul, 2002. Dinosaurs of the Air. The John Hopkins University Press, Baltimore and London. 460 pp.

Eumaniraptora Padian, Hutchinson and Holtz, 1997
Definition- (Deinonychus antirrhopus + Passer domesticus) (Maryanska, Osmólska and Wolsan, 2002; modified from Padian, Hutchinson and Holtz, 1997)
Other definitions- (Passer domesticus <- Troodon formosus) (modified from Agnolín and Novas, 2013)
(Dromaeosaurus albertensis + Passer domesticus) (Godefroit, Cau, Hu, Escuillié, Wu and Dyke, 2013)
(Deinonychus antirrhopus + Vultur gryphus) (Cau, Beyrand, Voeten, Fernandez, Tafforeau, Stein, Barsbold, Tsogtbaatar, Currie and Godefroit, 2017)
(Passer domesticus <- Anchiornis huxleyi) (Lefèvre, Cau, Cincotta, Hu, Chinsamy, Escuillié and Godefroit, 2017)
= Aves sensu Chiappe, 1992
Definition- (Archaeopteryx lithographica + Passer domesticus)
= Maniraptora sensu Holtz and Padian, 1995
Definition- (Dromaeosaurus albertensis + Passer domesticus)
= Avialae sensu Wagner and Gauthier, 1999
Definition- (Archaeopteryx lithographica + Vultur gryphus)
= Avemorpha Miller, 2004
= Palaeoaves Livezey and Zusi, 2007
= Ornithes Martyniuk, 2012
Definition- (Archaeopteryx lithographica + Passer domesticus)
= Avialae sensu Agnolín and Novas, 2013
Definition- (Archaeopteryx lithographica + Passer domesticus) (modified)
= Eumaniraptora sensu Cau, Beyrand, Voeten, Fernandez, Tafforeau, Stein, Barsbold, Tsogtbaatar, Currie and Godefroit, 2017
Definition- (Deinonychus antirrhopus + Vultur gryphus)
Comments- Holtz (1992) originally named Eumaniraptora in his unpublished thesis, but used it for what would now be called Maniraptoriformes- a clade containing paravians, oviraptorosaurs, ornithomimosaurs and also tyrannosaurids, but not Ornitholestes or Compsognathus. Padian et al. (1997) in an abstract named it as a new node "to unite the stem taxa Deinonychosauria and Avialae", though without an explicit definition. Their definitions of Deinonychosauria and Avialae imply a definition of Deinonychus + Aves, however. It was first used outside an abstract by Padian et al. (1999), and Maryanska et al. (2002) provided species-level specifiers.
Miller (2004) proposed Avemorpha for the clade including dromaeosaurids and avialans (but not Archaeopteryx), but this is a junior synonym of Eumaniraptora.
Palaeoaves is used as a paraphyletic parvclass within Avialae by Livezey and Zusi (2007) that includes Archaeopteryx, Rahonavis, Confuciusornis, enantiornithines and Apsaravis, but not hesperornithines, Ichthyornis, lithornithids or Aves sensu stricto.
Martyniuk (2012) erected Ornithes for "< Archaeopteryx lithographica & Passer domesticus", which is not especially useful as it could include or exclude unenlagiids, troodontids and dromaeosaurids in trees only a steps apart in Hartman et al.'s analysis.
References- Chiappe, 1992. Enantiornithine (Aves) tarsometatarsi and the avian affinites of the Cretaceous Avisauridae. Journal of Vertebrate Paleontology. 12(3), 344-350.
Holtz, 1992. An unusual structure of the metatarsus of Theropoda (Archosauria: Dinosauria: Saurischia) of the Cretaceous. Unpublished PhD thesis. Yale University. 347 pp.
Holtz and Padian, 1995. Definition and diagnosis of Theropoda and related taxa. Journal of Vertebrate Paleontology. 15(3), 35A.
Padian, Hutchinson and Holtz, 1997. Phylogenetic definitions and nomenclature of the major taxonomic categories of the theropod dinosaurs. Journal of Vertebrate Paleontology. 17(3), 68A.
Padian, Hutchinson and Holtz, 1999. Phylogenetic definitions and nomenclature of the major taxonomic categories of the carnivorous Dinosauria (Theropoda). Journal of Vertebrate Paleontology. 19(1), 69-80.
Wagner and Gauthier, 1999. 1,2,3 5 2,3,4: A solution to the problem of the homology of the digits in the avian hand. Proceedings of the National Academy of Sciences. 96, 5111-5116.
Maryanska, Osmólska and Wolsan, 2002. Avialan status for Oviraptorosauria. Acta Palaeontologica Polonica. 47 (1), 97-116.
Miller, 2004. A new phylogeny of the Dromaeosauridae. 2004 Student Showcase Journal. 20, 123-158.
Livezey and Zusi, 2007. Higher-order phylogeny of modern birds (Theropoda, Aves: Neornithes) based on comparative anatomy. II. Analysis and discussion. Zoological Journal of the Linnean Society. 149 (1), 1-95.
Lamm, Ksepka, Stone and Clarke, 2008. Identifying differential size trends in Mesozoic birds using new data and a novel method. Journal of Vertebrate Paleontology. 28(3), 103A.
Bell, Chiappe and O'Connor, 2009. Ecological diversity of Mesozoic birds: Morphometric analysis with a phylogenetic perspective. Journal of Vertebrate Paleontology. 29(3), 61A.
Chinsamy-Turan, 2009. The bone microstructure of Mesozoic birds. Journal of Vertebrate Paleontology. 29(3), 77A.
Nudds and Dyke, 2009. Estimating the flight capabilities of extinct Mesozoic birds from their primary feather morphology. Journal of Vertebrate Paleontology. 29(3), 156A-157A.
O'Connor, 2009. A comprehensive phylogeny of Mesozoic birds. Journal of Vertebrate Paleontology. 29(3), 157A.
Weishampel and Habib, 2009. Flight morphology and launch dynamics of basal birds, and the potential for competition with pterosaurs. Journal of Vertebrate Paleontology. 29(3), 199A.
Wang, Dyke and Nudds, 2010. Inferring the flight styles of early birds and flight evolution from primary feather length. Journal of Vertebrate Paleontology. Program and Abstracts 2010, 183A.
Dececchi and Larsson, 2011. The origin of wings. Journal of Vertebrate Paleontology. Program and Abstracts 2011, 97.
Wang, Dyke and Palmer, 2011. Scaling in size and stiffness of avian primary feathers: Implications for the strength of Mesozoic bird feathers. Journal of Vertebrate Paleontology. Program and Abstracts 2011, 211.
Dececchi, 2012. Patterns and processes at origin of birds: Macroevolutionary tempo and mode. Journal of Vertebrate Paleontology. Program and Abstracts 2012, 85-86.
Martyniuk, 2012. A Field Guide to Mesozoic Birds and Other Winged Dinosaurs. Vernon, New Jersey. Pan Aves. 189 pp.
Mitchell, Makovicky and Gao, 2012. Paleoecology of the Jehol birds inferred from modern bird ecomorphology. Journal of Vertebrate Paleontology. Program and Abstracts 2012, 143.
O'Connor, 2012. Dietary evolution in Mesozoic birds. Journal of Vertebrate Paleontology. Program and Abstracts 2012, 151.
Agnolín and Novas, 2013. Avian ancestors: A review of the phylogenetic relationships of the theropods Unenlagiidae, Microraptoria, Anchiornis and Scansoriopterygidae. Springer Netherlands. 96 pp.
Dececchi, Habib and Larsson, 2013. Testing wing assusted incline running (WAIR): Investigating the terrestrial origin of the avian flight stroke. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 113.
Field and Lynner, 2013. Precise inference of avialan flight ability from shoulder joint dimensions. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 126.
Godefroit, Cau, Hu, Escuillié, Wu and Dyke, 2013. A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds. Nature. 498, 359-362.
Xu, Zhao and Han, 2013. Homeotic transformation in the evolution of the theropod semilunate carpal. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 241.
Naish, 2014. The fossil record of bird behaviour. Journal of Zoology. 292(4), 268-280.
O'Connor and Zhou, 2014. Earliest stages in the evolution of the modern avian skeleton: Archaeopteryx and the Jehol avifauna compared. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 197.
Sanz, Serrano, Martin-Serra and Palmqvist, 2014. Revisiting size trends in early stem birds. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 221.
Serrano, Palmqvist, Martin-Serra and Sanz, 2014. Morphofunctional evolution of the humerus in the avian lineage. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 228.
Cau, Beyrand, Voeten, Fernandez, Tafforeau, Stein, Barsbold, Tsogtbaatar, Currie and Godefroit, 2017. Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs. Nature. 552, 395-399.
Lefèvre, Cau, Cincotta, Hu, Chinsamy, Escuillié and Godefroit, 2017. A new Jurassic theropod from China documents a transitional step in the macrostructure of feathers. The Science of Nature. 104:74.

Eumaniraptora incertae sedis

Cretaaviculus Bazhanov, 1969
C. sarysuensis Bazhanov, 1969
Santonian, Late Cretaceous
Bostobe Formation, Kazakhstan
Holotype- contour feather (17 mm)
Comments- This specimen is a small, asymmetric contour feather with a length of 17 mm and a width of 4.8-5.5 mm. The barbs are at a 20 degree angle to the shaft. The asymmetry suggests it is a paravian. Nessov (1992) considers it indeterminate, which is true so far as feather characteristics cannot be used to diagnose Mesozoic birds.
References- Bazhanov, 1969. [On the record of a bird remain living in the Cretaceous in the USSR]. Tezisy Dokladov XV Sessii Vsesoyuznogo Paleontologicheskogo Obshchestva. 5-6.
Shillin and Romanova, 1978. [Senonian floras of Kazakhstan]. Alma-Ata: Kairat Publishing. 176 pp.
Nessov, 1992. Mesozoic and Paleogene birds of the USSR and their paleoenvironments. in Campbell (ed). Papers in Avian Paleontology Honoring Pierce Brodkorb. 465-478.

Eumaniraptora indet. (Lambe, 1902)
Late Campanian, Late Cretaceous
Dinosaur Park Formation of the Judith River Group, Alberta, Canada
Material- (CMN coll.) proximal caudal vertebra (Lambe, 1902)
Comments- The CMN vertebra was identified by Lambe (1902) as a posterior dorsal tentatively referred to Struthiomimus (his Ornithomimus altus) (plate XV figure 6-8), but is actually a caudal, and may be Troodon or Saurornitholestes based on its low square articular face, amphicoelous centrum and lack of a pleurocoel.
References- Lambe, 1902. New genera and species from the Belly River Series (Mid-Cretaceous). Geological Survey of Canada Contributions to Canadian Palaeontology. 3(2), 25-81.

unnamed eumaniraptoran (Dumont, Tafforeau, Bertin, Bhullar, Field, Schulp, Strilisky, Thivichon-Prince, Viriot and Louchart, 2016)
Late Maastrichtian, Late Cretaceous
Scollard Formation, Alberta, Canada
Material- (RTMP 94.31.32) tooth
Comments- Initially identified as Aves indet. based on the small size, the completely serrated distal edge suggests otherwise. Both edges are straight with a smooth carina at the base of the mesial esdge.
Reference- Dumont, Tafforeau, Bertin, Bhullar, Field, Schulp, Strilisky, Thivichon-Prince, Viriot and Louchart, 2016. Synchrotron imaging of dentition provides insights into the biology of Hesperornis and Ichthyornis, the "last" toothed birds. BMC Evolutionary Biology. 16:178.

unnamed possible eumaniraptoran (Gates, Zanno and Makovicky, 2015)
Late Maastrichtian, Late Cretaceous
Hell Creek Formation, South Dakota, US
Material- (FMNH PR2900) tooth (4.4x2.2x1 mm)
Comments- This is an anterior tooth which lacks serrations and a basal constriction
Reference- Gates, Zanno and Makovicky, 2015. Theropod teeth from the upper Maastrichtian Hell Creek Formation "Sue" Quarry: New morphotypes and faunal comparisons. Acta Palaeontologica Polonica. 60(1), 131-139.

Eumaniraptora indet. (Kessler and Jurcsak, 1984)
Late Berriasian-Early Valanginian, Early Cretaceous
Cornet bauxite, Bihor, Romania
Material- (MTCO 17558; = MTCO-P 207; paratype of Limnornis corneti) proximal scapula
?(MTCO 17966) proximal radius
?(MTCO 17982) partial furcula
Comments- Kessler (1984) noted approximately sixty bird-like fragments from the Cornet bauxite, six of which can "with certainty be attributed to birds." These are the holotypes of Eurolimnornis corneti and Palaeocursornis corneti in addition to other isolated fragments, but most have been moved to Pterosauria or more generally Ornithodira and Archosauria indet. by Dyke et al. (2011) and Agnolín and Varricchio (2012).
MTCO 17558 was originally (Kessler and Jurcsak, 1984) decribed as a partial carpometacarpus and paratype of Limnornis corneti (later renamed Palaeocursornis corneti), and later (Kessler and Jurcsak, 1986) a paratype of Eurolimnornis corneti. Kurochkin (1995) used the carpometacarpus identification to argue for avian affinities of Eurolimnornis due to supposed distal fusion and tendinal sulcus, but Hope (2002) noted these are also present in Ichthyornis. Hope also noted it couldn't be referred definitively to Eurolimnornis or Palaeocursornis, and Dyke et al. reinterpreted it as a bird proximal scapula (though they probably mistakenly wrote it is not identifiable as a bird).
MTCO 17966 and 17982 were stated to be birds by Dyke et al., but that identity was doubted by Agnolín and Varricchio.
References- Kessler, 1984. Lower Cretaceous birds from Cornet, Roumania. In Rief and Westphal (eds.). Third Symposium on Mesozoic Terrestrial Ecosystems, Tubingen. 119-121.
Kessler and Jurcsak, 1984. Fossil bird remains in the bauxite from Cornet (Romania, Bihor County). Travaux du Musee d'Histoire Naturelle, Grigore Antipa. 25, 393-401.
Kessler and Jurcsak, 1986. New contributions to the knowledge of the Lower Cretaceous bird remains from Cornet (Romania). Travaux du Musee d'Histoire Naturelle, Grigore Antipa. 28, 289-295.
Kurochkin, 1995. Synopsis of Mesozoic birds and early evolution of class Aves. Archaeopteryx. 13, 47-66.
Hope, 2002. The Mesozoic radiation of Neornithes. In Chiappe and Witmer (eds.). Mesozoic birds: Above the Heads of Dinosaurs. University of California Press. 339-388.
Dyke, Benton, Posmosanu and Naish, 2011. Early Cretaceous (Berriasian) birds and pterosaurs from the Cornet bauxite mine, Romania. Palaeontology. 54(1), 79-95.
Agnolín and Varricchio, 2012 . Systematic reinterpretation of Piksi barbarulna Varricchio, 2002 from the Two Medicine Formation (Upper Cretaceous) of western USA (Montana) as a pterosaur rather than a bird. Geodiversitas. 34(4), 883-894.

unnamed Eumaniraptora (Peñalver, Arillo, Delclòs, Peris, Grimaldi, Anderson, Nascimbene and Pérez-de la Fuente, 2017)
Early Cenomanian, Late Cretaceous
Noije bum mines, Myanmar
Material- (AMNH Bu JZC-F18) feather, feather fragments (Peñalver, Arillo, Delclòs, Peris, Grimaldi, Anderson, Nascimbene and Pérez-de la Fuente, 2017)
(LV-0321) distal phalanx II-1, phalanx II-2 (4.7 mm), manual ungual II (2 mm), manual claw sheath, remiges (Xing, McKellar and O'Connor, 2020)
Comments- Peñalver et al. (2017) describe an amber sample (AMNH Bu JZC-F18) containing a feather, ixodid tick nymph and other arthropods. The feather is asymmetrical with barbules, indicating it belonged to a eumaniraptoran. St. Fleur's (2017) newspaper article says "the tick was a nymph ... and that its host was most likely some sort of fledgling dinosaur no bigger than a hummingbird, which Dr. Grimaldi referred to as a "nanoraptor."" Yet nothing in Peñalver et al. suggests the age or size of the dinosaur, and the term "nanoraptor" misleadingly suggests a deinonychosaur or oviraptorosaur instead of an avialan. When the article later states "the host was more likely a nonavian dinosaur and not a modern bird based on molecular dating", its using 'avian' in the crown Aves sense without explicitly stating so, correlating to Peñalver et al.'s statement "crown-group birds are excluded as possible hosts because their inferred age is significantly younger than Burmese amber." Yet there are several groups such as confuciusornithiforms and enantiornithines, the latter known from multiple specimens in Myanmar amber, that are plausible sources of the feather and hosts of the ixodid ticks but which would not be considered raptors in the colloquial sense. It's also possible AMNH Bu JZC-F18 is from e.g. an archaeopterygid or microraptorian, but nothing in the feather's structure or stratigraphy has favored any particular option, and "nanoraptor" is here considered a hypothetical animal akin to "proavis" and not a nomenclatural suggestion for the taxon which grew the preserved feather.
Xing et al. (2020) described distal wing LV-0321 which has asymmetrical remiges with barbules, so is eumaniraptoran. Given its size, this is either an extremely young juvenile or an ornithothoracine, and the plumage gives no indication of juvenile status. Tha size of the manual ungual compared to the phalanx is less than deinonychosaurs except Buitreraptor, but the phalanx is not incredibly elongate as it is in that genus. The ratio is similar to Fukuipteryx, Zhongornis and some ornithothoracines.
References- Peñalver, Arillo, Delclòs, Peris, Grimaldi, Anderson, Nascimbene and Pérez-de la Fuente, 2017. Ticks parasitised feathered dinosaurs as revealed by Cretaceous amber assemblages. Nature Communications. 8: 1924.
St. Fleur, 2017. Ticks trapped in amber were likely sucking dinosaur blood. The New York Times. December 12.
Xing, McKellar and O'Connor, 2020. An unusually large bird wing in mid-Cretaceous Burmese amber. Cretaceous Research. Journal Pre-proof DOI: 10.1016/j.cretres.2020.104412

unnamed possible eumaniraptoran (Riff, Kellner, Mader and Russell, 2002)
Cenomanian, Late Cretaceous
Kem Kem beds, Morocco
Material- (CMN 50852) incomplete dorsal vertebra (21 mm)
Comments- Riff et al. (2002, 2004) considered this most similar to Rahonavis, though it differs in being more elongate, having a larger neural canal and lacking pleurocoels or lateral fossae. Chiarenza and Cau (2016) stated the specimen lacked unambiguous paravian or avialan characters, noting in particular the large neural canal is present in many small theropods and crocodyliforms.
References- Riff, Kellner, Mader and Russell, 2002. On the occurence of an avian vertebra in Cretaceous strata of Morocco, Africa. Anais da Academia Brasileira de Ciencias. 74(2), 367-368.
Riff, Mader, Kellner and Russell, 2004. An avian vertebra from the continental Cretaceous of Morocco, Africa. Arquivos do Museu Nacional. 62(2), 217-223.
Chiarenza and Cau, 2016. A large abelisaurid (Dinosauria, Theropoda) from Morocco and comments on the Cenomanian theropods from North Africa. PeerJ. 4:e1754.

undescribed eumaniraptoran (Naish, Martill and Merrick, 2007)
Late Aptian, Early Cretaceous
Nova Olinda Member of the Crato Formation, Brazil
Material- (Senckenberg Museum coll.) carpals, three remiges (14, 81 mm)
Comments- Naish et al. (2007) discuss this as bird remains, but as e.g. Microraptor has asymmetrical feathers too, it may be from another kind of paravian.
Reference- Naish, Martill and Merrick, 2007. Birds of the Crato Formation. In: Martill, Bechly and Loveridge (eds.). The Crato fossil beds of Brazil: Window into an ancient world. Cambridge University Press. 525-533.

Deinonychosauria Colbert and Russell, 1969
Definition- (Deinonychus antirrhopus <- Passer domesticus) (Holtz and Osmólska, 2004; Padian, 1997)
Other definitions- (Troodon formosus + Dromaeosaurus albertensis) (Holtz and Osmólska, 2004; modified from Sereno, 1997)
(Troodon formosus + Velociraptor mongoliensis) (modified from Sereno, 1998)
(Dromaeosaurus albertensis <- Passer domesticus) (Godefroit, Demuynck, Dyke, Hu, Escuillié and Claeys, 2013)
(Troodon formosus + Velociraptor mongoliensis, - Passer domesticus) (Hendrickx, Hartman and Mateus, 2015)
(Troodon formosus + Velociraptor mongoliensis, - Ornithomimus edmontonicus, Passer domesticus) (Sereno, online 2005)
= Saurornithes Nicholson, 1878a/b
Definition- (Archaeopteryx lithographica <- Passer domesticus) (Martyniuk, 2012)
= Dromaeosauria Bonaparte and Novas, 1985
= Archaeopteryx sensu Sereno, 1998
Definition- (Archaeopteryx lithographica <- Passer domesticus) (modified)
= Archaeopterygidae sensu Sereno, online 2005
Defrinition- (Archaeopteryx lithographica <- Passer domesticus)
= Dromaeosauridae sensu Godefroit, Demuynck, Dyke, Hu, Escuillié and Claeys, 2013
Definition - (Dromaeosaurus albertensis <- Passer domesticus)
= Tetrapterygidae Chatterjee, 2015
Deinonychosauria defined- There have been two basic suggested definitions for Deinonychosauria, one stem-based (Deinonychus <- Passer) by Padian (1997) and the other node based (Troodon + dromaeosaurids) by Sereno (1997). I prefer Padian's because it is based on the eponymous genus, and Colbert and Russell (1969) did not originally specify the inclusion of troodontids. They only include dromaeosaurids in the taxon, and only mention Dromaeosaurus, Deinonychus and Velociraptor as members of that family. Furthermore, this gives a name to the clade including archaeopterygids and unenlagiids in some most parsimonious topologies and ensures Deinonychosauria does not self destruct or include Aves.
Referral of isolated teeth- With very limited exceptions, theropod teeth with constricted roots are from Maniraptoriformes, and except for therizinosaurs basically all serrated varieties are from deinonychosaurs. The only(?) known exception is irregularily developed distal crenulations on Longipteryx premaxillary teeth (Wang et al., 2015), with supposed avialan teeth described by Sankey et al. (2002) from the Dinosaur Park Formation not associated with cranial or skeletal material to verify their identity. Thus serrated paravian teeth are here referred to Deinonychosauria, though trees almost as short as the one used here placed taxa with serrated teeth like troodontids as avialans.
Dromaeosauria- While the term 'dromaeosaur' is a common short form of dromaeosaurid, use of Dromaeosauria itself is much rarer in the published literature. The earliest example of the latter may be Bonaparte and Novas (1985) who seem to treat Dromaeosauria (containing at least Dromaeosaurus) as a theropod group on par with Carnosauria and Segnosauria. Similarly, Dubois (2006) proposed Dromaeosauria alongside Aves at the level of phalanx, between family and order, but his scheme of new Linnaean levels was not widely adopted. Fossilworks (online 2007) presents Chatterjee and Templin (2007) as the authors of Dromaeosauria, who use it in a cladogram as a eumaniraptoran clade containing Microraptor and Pedopenna, sister to Aves (Avialae in official usage). Other examples are mistakes for Dromaeosauridae or Eudromaeosauria.
Tetrapterygidae- Chatterjee (2015) proposed the family Tetrapterygidae for a clade including Microraptor, Xiaotingia, Anchiornis and Aurornis. However, as noted by Martyniuk (online, 2015), according to ICZN Article 11.7.11 a family-group name must be "formed from the stem of an available generic name" which "must be a name then used as valid in the new family-group taxon." As Chatterjee did not intend for Tetrapterygidae to include a genus Tetrapteryx, it is invalid. Furthermore, Tetrapteryx has already been used for a genus of gruid bird (Thunberg, 1818), corrently considered a synonym of Anthropoides. Finally, if Microraptor is in a family, the family must be named Microraptoridae because that family was already erected by Longrich and Currie (2009).
References- Thunberg, 1818. Tetrapteryx capensis, ett nytt Fogelslaegte. Kongliga Svenska Vetenskaps Academiens nya Handlingar. 1818(2), 242-245.
Nicholson, 1878a. A Manual of Zoology for the Use of Students with a General Introduction on the Principles of Zoology. Blackwood and Sons: Edinburgh and London. 800 pp.
Nicholson, 1878b. Advanced Text-Book of Zoology for Junior Students. Blackwood and Sons: Edinburgh and London. 405 pp.
Colbert and Russell, 1969. The small Cretaceous dinosaur Dromaeosaurus. American Museum Novitates. 2380, 49 pp.
Bonaparte and Novas, 1985. Abelisaurus comahuensis, n. g., n. sp., Carnosauria from the Late Cretaceous of Patagonia. Ameghiniana. 21, 259-265.
Padian, 1997. Avialae. In Currie and Padian (eds.). Encyclopedia of Dinosaurs. Elsevier Inc. 39-40.
Sereno, 1997. The origin and evolution of dinosaurs. Annual Review of Earth and Planetary Sciences. 25, 435-489.
Sereno, 1998. A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen. 210(1), 41-83.
Sankey, Brinkman, Guenther and Currie, 2002. Small theropod and bird teeth from the Late Cretaceous (Late Campanian) Judith River Group, Alberta. Journal of Paleontology. 76(4), 751-763.
Godefroit, Demuynck, Dyke, Hu, Escuillié and Claeys, 2013b. Reduced plumage and flight ability of a new Jurassic paravian theropod from China. Nature Communications. 4(1), 1394.
Holtz and Osmólska, 2004. Saurischia. In Weishampel, Dodson and Osmólska (eds.). The Dinosauria Second Edition. University of California Press. 21-24.
Sereno, online 2005. Stem Archosauria - TaxonSearch. http://www.taxonsearch.org/dev/file_home.php [version 1.0, 2005 November 7]
Dubois, 2006. Proposed rules for the incorporation of nomina of higher-ranked zoological taxa in the International Code of Zoological Nomenclature. 2. The proposed rules and their rationale. Zoosystema. 28(1), 165-258.
Chatterjee and Templin, 2007. Biplane wing planform and flight performance of the feathered dinosaur Microraptor gui. Proceedings of the National Academy of Sciences, 104(5), 1576-1580.
Fossilworks, online 2007. http://fossilworks.org/?a=referenceInfo&reference_no=19832
Longrich and Currie, 2009. A microraptorine (Dinosauria - Dromaeosauridae) from the Late Cretaceous of North America. Proceedings of the National Academy of Sciences. 106(13), 5002-5007.
Martyniuk, 2012. A Field Guide to Mesozoic Birds and Other Winged Dinosaurs. Vernon, New Jersey. Pan Aves. 189 pp.
Chatterjee, 2015. The Rise of Birds: 225 Million Years of Evolution. Second Edition. Johns Hopkins University Press. 392 pp.
Hendrickx, Hartman and Mateus, 2015. An overview of non-avian theropod discoveries and classification. PalArch's Journal of Vertebrate Palaeontology. 12(1), 1-73.
Chatterjee, 2015. The Rise of Birds: 225 Million Years of Evolution. Second Edition. Johns Hopkins University Press. 392 pp.
Martynuik, online 2015. https://web.archive.org/web/20150927175357/http://dinogoss.blogspot.com/2015/05/the-crane-and-microraptor.html
Wang, Zhao, Shen, Liu, Gao, Cheng and Zhang, 2015. New material of Longipteryx (Aves: Enantiornithes) from the Lower Cretaceous Yixian Formation of China with the first recognized avian tooth crenulations. Zootaxa. 3941(4), 565-578.

undescribed Deinonychosauria (Ikejiri, Watkins and Gray, 2006)
Late Kimmeridgian, Late Jurassic
Brushy Basin Member of the Morrison Formation, Wyoming, US
Material- (WDC BS-641) tooth (9.1 x 9.2 x 4.2 mm)
(WDC BS-885) tooth (12.6 x 8.3 x 3.6 mm)
(WDC BS-889) tooth (12.2 x 7 x 3.2 mm)
Comments- Called "deinonychosaurid(?)" in the measurements table, Ikejiri et al. (2006) describe these are more recurved and transversely compressed than Allosaurus, with relatively larger serrations, high DSDI and smooth enamel. They furthermore state WDC BS-641 has mesial serrations conficed to the apical fifth.
Reference- Ikejiri, Watkins and Gray, 2006. Stratigraphy, sedimentology, and taphonomy of a sauropod quarry from the Upper Jurassic Morrison Formation of Themopolis, central Wyoming. In Foster and Lucas (eds.). New Mexico Museum of Natural History Bulletin. 36, 36-46.

unnamed deinonychosaur (Rodriguez de la Rosa and Cevallos-Ferriz, 1998)
Early Maastrichtian, Late Cretaceous
Cañon del Tule Formation, Mexico
Material- (IGM-7711) pedal phalanx II-I (18.8 mm)
(IGM-7712) pedal phalanx II-2 (21.7 mm)
Comments- Although described as being from the Cerro del Pueblo Formation, Aguillon Martinez (2010) found this and other material from the El Pelillal locality belong to the later Cañon del Tule Formation.
These may belong to the same individual, which was tentatively referred to Troodontidae by Rodriguez de la Rosa and Cevallos-Ferriz (1998) based on the centrally placed collateral ligament pit, which is also found in Saurornithoides and Troodon. However, the longer II-2 compared to II-1 is more similar to archaeopterygids and dromaeosaurids. It is from a different taxon than IGM-7710 as it is not nearly as elongate, and different from IGM-7715 as it has a centrally placed collateral ligament pit.
References- Rodriguez de la Rosa and Cevallos-Ferriz, 1998. Vertebrates of the El Pelillal locality (Campanian, Cerro del Pueblo Formation), Southeastern Coahuila, Mexico. Journal of Vertebrate Paleontology. 18, 751-764.
Aguillon Martinez, 2010. Fossil vertebrates from the Cerro del Pueblo Formation, Coahuila, Mexico, and the distribution of Late Campanian (Cretaceous) terrestrial vertebrate faunas. MS thesis, Dedman College Southern Methodist University. 135 pp.

unnamed deinonychosaur (Weigert 1995)
Early Kimmeridgian, Late Jurassic
Alcobaca Formation, Portugal
Material- (IPFUB GUI ARCH. 1) tooth
(IPFUB GUI ARCH. 3) tooth
(IPFUB GUI ARCH. 4) tooth
(IPFUB GUI ARCH. 5) tooth
(IPFUB GUI ARCH. 7) tooth
(IPFUB GUI ARCH. coll.) 98 teeth (1-2.6 mm)
Comments- Weigert (1995) assigned these teeth to cf. Archaeopteryx sp..
These teeth are constricted basally, with mesial and distal carinae. Both lingual and labial surfaces are generally smooth, and the lingual surface is concave apically. The labial surface sometimes has faint grooves, which were believed to be from wear. Eighty-six teeth have both mesial and distal serrations, while the other seventeen sometimes lack mesial serrations and have carinae shifted lingually, so are probably premaxillary teeth. The teeth average 1.65 mm in crown height and .60 mm in FABL. Serrations are low and rounded or slightly pointed, with a miniscule size of 24/mm.
The specimens differ from Archaeopteryx and most other archaeopterygids in having serrations. Weigert (1995) states these may be present but hidden in the former genus, since most Archaeopteryx teeth are only visible in labial view, where the serrations cannot be seen in the Portuguese specimens. Yet the London and Munich specimens of Archaeopteryx both expose serrationless teeth in lingual view, showing Weigert is incorrect. He explained the absence of serrations in the Munich specimen by claiming it was a distinct species (A. bavarica) which may have differed from A. lithographica in this respect, but this is special pleading, and the distinctness of A. bavarica is very poorly supported (see discussion in Archaeopteryx entry). The diagonally oriented carina on the apical half of the tooth is described as an archaeopterygiform apomorphy, but this is true of any teeth which share the same stout, highly recurved outline (e.g. Sinornithoides). The other cited archaeopterygiform apomorphy is the lingually projected mesial carina, but this is found in other taxa such as Sinornithosaurus' anterior teeth. The teeth do seem to be maniraptoriform, based on the constricted crown base, and are not referrable to several groups due to their serrations (Ornithomimosauria, Alvarezsauroidea, Oviraptorosauria, Avialae), but also lack the enlarged serrations found in most therizinosaurs and derived troodontids.
Reference- Weigert, 1995. Isolated teeth of cf. Archaeopteryx sp. from the Upper Jurassic of the coalmine Guimarota (Portugal. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte. 9, 562-576.

unnamed deinonychosaur (Buffetaut, Marandat and Sige, 1986)
Late Cretaceous
Serviers, Gard, France
Material- (Universite des Sciences et Techniques de Languedoc SER 03) partial tooth (~2.2 mm)
Comments- This tooth is relatively elongate and barely recurved. It has 14 distal serrations per mm, while the mesial serrations are indistinct. It was assigned to Dromaeosauridae by Buffetaut et al. (1986), but is most similar to supposed bird teeth from the Dinosaur Park Formation in its small size, tiny serrations, lack of much recurvature, and constricted base.
References- Buffetaut, Marandat and Sige, 1986. Decourvert de dents de Deinonychosaures (Saurischia, Theropoda) dans le Creace superieur du Sud de la France. Les Comptes rendus de l'Académie des sciences. 303, Serie II(15), 1393-1396.

unnamed deinonychosaur (Buffetaut, Marandat and Sige, 1986)
Late Campanian-Early Maastrichtian, Late Cretaceous
Champ-Garimond, Gard, France
Material- (Universite des Sciences et Techniques de Languedoc CHG 48) tooth (1.9 mm)
Comments- This tooth is short and slightly recurved, with a constricted base. There are 15 distal serrations per millimeter, while mesial serrations are only present as fine outlines. Like SER 03, it was assigned to Dromaeosauridae by Buffetaut et al. (1986), but is most similar to supposed bird teeth from the Dinosaur Park Formation in its small size, tiny serrations which are absent mesially, lack of much recurvature, and constricted base.
References- Buffetaut, Marandat and Sige, 1986. Decourvert de dents de Deinonychosaures (Saurischia, Theropoda) dans le Creace superieur du Sud de la France. Les Comptes rendus de l'Académie des sciences. 303, Serie II(15), 1393-1396.

undescribed deinonychosaur (Debeljak, Kosir and Otonicar, 1999)
Campanian-Maastrichtian, Late Cretaceous
Kozina, Slovenia
Material- (ACKK-D-8/088; 5th morphotype) tooth (~4.9x~3.2x? mm) (Debeljak, Kosir, Buffetaut and Otonicar, 2002)
Comments- This tooth is slightly recurved with a constricted root, serrated both mesially (at least apical half) and distally with rounded, small and subequal denticles. While stated to be "more troodontid-like" and referred to "? Troodontidae", the combination of characters is unlike that family and the tooth is here referred to Deinonychosauria.
References- Debeljak, Kosir and Otonicar, 1999. A preliminary note on dinosaurs and non-dinosaurian reptiles from the Upper Cretaceous carbonate platform succession at Kozina (SW Slovenia). Dissertationes / Academia Scientiarum et Artium Slovenica. Classis IV, Historia naturalis. 40, 3-25.
Debeljak, Kosir, Buffetaut and Otonicar, 2002. The Late Cretaceous dinosaurs and crocodiles of Kozina (SW Slovenia): A preliminary study. Memorie della Societa Geologica Italiana. 57, 193-201.

unnamed Deinonychosauria (Csiki and Grigorescu, 1998)
Late Maastrichtian, Late Cretaceous
Sinpetru Beds, Romania
Material- (FGGUB R.1318) tooth (12.5x8x5.3 mm)
(FGGUB R.1319) tooth (11x8x5 mm)
(FGGUB R.1320) tooth (5.3x2.9x? mm)
(MAFI v.12685a) tooth (11.2x5.8x4.1 mm)
(MAFI v.12685b) tooth (8x3.9x2.3 mm)
Comments- These teeth are slightly recurved with constricted roots, poorly developed blood pits and small rectanguilar serrations (~5/mm) which are present and similarly sized (DSDI .91-1) on both carinae. While they were described as troodontid-like, only Troodon and Hesperornithoides have mesial serrations, and the Sinpetru teeth seem more similar to Microraptor than to any of those (large and hooked serrations in Troodon, highly recurved crowns with apically limited mesial serrations and high DSDI in Hesperornithoides). They are thus only referred to Deinonychosauria here, which have poorly established identifications in Cretaceous Europe.
Reference- Csiki and Grigorescu, 1998. Small theropods from the Late Cretaceous of the Hateg basin (western Romania) - An unexpected diversity at the top of the food chain. Oryctos. 1, 87-104.

undescribed Deinonychosauria (Nessov, 1977)
Early Cenomanian, Late Cretaceous
Khodzhakul Formation, Uzbekistan
Material- teeth
Comments- From Sheikhdzheili II "teeth of Deinonychosauria (identification by A. K. Rozhdestvensky from collections made by the author)" and from Khodzhakulsai "teeth of ?Deinonychosauria** (Nessov, 1977)" ("Discoveries made by [Nessov]'s assistants or by [Nessov] himself and identified by [Nessov] are marked with two asterisks").
References- Nessov, 1977. [Turtles and some other reptiles of the Cretaceous of Karakalpakia]. Voprosy gyerpyetology. Chyetvyertaya Vsyesoyuznaya Gyerpyetologichyeskaya konfyeryentsiya, Lyeningrad. Avtoryefyerat doklada. Lyeningrad, Nauka. 155-156.
Nessov, 1995. Dinosaurs of northern Eurasia: New data about assemblages, ecology, and paleobiogeography. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University, St. Petersburg. 1-156.

unnamed deinonychosaur (Wang, Cau, Wang, Yu, Wu, Wang and Liu, 2023 online)
Early Aptian, Early Cretaceous
Pigeon Hill, Longjiang Formation, Inner Mongolia, China
Material- (LY 2022JZ3004) fragmentary proximal caudal vertebrae, fragmentary sacrum/ilium, proximal pubes, ischia (~50 mm), incomplete femora (~134 mm), proximal tibia, proximal fibula, pedal phalanx (~15 mm), fragmentary pedal phalanges, pedal ungual
Comments- This was discovered in 2022. Wang et al. (2023) note "the material is comparable in size to LY 2022JZ3001 [the Migmanychion type], the lack of evidence supporting their direct association prevents the referral of this material to the same individual." The recovery of Migmanychion here as a basal paravian using Hartman et al.'s maniraptoromorph matrix makes this plausible. Wang et al. found that "the small size of the ischium compared to the femur (ischium-to-femur ratio < 0.4) is more consistent with some early-diverging paravian clades than with oviraptorosaurs or other theropods (e.g., Anchiornithidae..." and further that "The slight cranioventral orientation of the pubis is plesiomorphic among maniraptorans and excludes this specimen from late-diverging deinonychosaurs, therizinosaurids, parvicursorines or avialans." Notably the large obturator process excludes this specimen from Avialae in the current topology, making it likely to be a deinonychosaur.
Reference- Wang, Cau, Wang, Yu, Wu, Wang and Liu, 2023 online. A new theropod dinosaur from the Lower Cretaceous Longjiang Formation of Inner Mongolia (China). Cretaceous Research. Journal Pre-proof, 10565. DOI: 10.1016/j.cretres.2023.105605.

unnamed deinonychosaur (Han, Clark, Xu, Sullivan, Choiniere and Hone, 2011)
Late Oxfordian, Late Jurassic
Wucaiwan, Upper Shishugou Formation, Xinjiang, China
Material- (IVPP V15850) tooth (4.8x3.9x2.5 mm)
Comments- Discovered by the Sino-American expeditions between 2001 and 2010, this is called Morphotype 7 by Han et al. (2011), who refer it to a troodontid. It is placed in Deinonychosauria here based on the combination of constricted base, recurvature and small serrations limited to part of the distal carina.
Reference- Han, Clark, Xu, Sullivan, Choiniere and Hone, 2011. Theropod teeth from the Middle-Upper Jurassic Shishugou Formation of northwest Xinjiang, China. Journal of Vertebrate Paleontology. 31(1), 111-126.

unnamed deinonychosaur (Dong, 1997)
Early Albian, Early Cretaceous
Upper Gray Beds of the Zhonggou Formation, Gansu, China
Material- (IVPP V11122-2) tooth (~.79x~.63x? mm)
Comments- This short recurved tooth with a basal constriction was reported to have mesial and distal serrations, both of which are much smaller than in e.g. Sinornithoides. It was referred to Troodontidae, but is here placed more generically in Deinonychosauria.
Reference- Dong, 1997. On small theropods from Mazongshan area, Gansu province, China. In Dong (ed.). Sino-Japanese Silk Road Dinosaur Expedition. China Ocean Press. 13-18.

unnamed possible deinonychosaur (Amiot, Buffetaut, Tong, Boudad and Kabiri, 2002)
Cenomanian, Late Cretaceous
Kem Kem beds, Morocco
Material- (M-ZA-017) tooth (14 mm) (Amiot, Buffetaut, Tong, Boudad and Kabiri, 2004)
Comments- This tooth is straight and short, with a BW/FABL of 0.6. The lingual side is concave, and the labial side convex. Both carinae have serrations which are apically inclined and lie on the midline. Mesial serrations (2/mm) and distal serrations (2.1/mm) have shallow interdenticle pits.
Amiot et al. (2002) first referred this specimen to Troodontidae based on the lens-shaped cross section, low DSDI, and large serrations which are apically inclined. They later (2004) referred it to Dromaeosauridae, as Currie said the base was too narrow and the serrations resembled dromaeosaurids. The serrations are not as large as troodontines, but many troodontids have small serrations anyway. This may also be a noasaurid anterior tooth, based on geography and resemblence to Vespersaurus.
References- Amiot, Buffetaut, Tong, Boudad and Kabiri, 2002. Laurasian theropod dinosaur teeth from the Late Cretaceous of Morocco. Conference abstract, Third Georges Cuvier Symposium, Montbeliard, France.
Amiot, Buffetaut, Tong, Boudad and Kabiri, 2004. Isolated theropod teeth from the Cenomanian of Morocco and their palaeobiogeographical significance. Revue de Paleobiologie, Geneve. 9, 143-149.

undescribed possible Deinonychosauria (Gallina, Apesteguía, Haluza and Canale, 2014)
Late Berriasian-Valanginian, Early Cretaceous
Bajada Colorada Formation, Neuquen, Argentina
Comments- Gallina et al. (2014) mentioned possible deinonychosaurs from this formation.
Reference- Gallina, Apesteguía, Haluza and Canale, 2014. A diplodocid sauropod survivor from the Early Cretaceous of South America. PLoS ONE. 9(5), e97128.

undescribed Deinonychosauria (Franco-Rosas, 2001)
Campanian-Maastrichtian, Late Cretaceous
Parecis Group, Brazil
Material- teeth
Comments- These were initially noted as being from the Cambambe Formation of the Bauru Group, but Bittencourt and Langer (2011) reassigned the locality to the later Parecis Group.
References- Franco-Rosas, 2001. Dentes de teropodomorfos da Formação Cambambe, Mato Grosso. Congresso Brasileiro de Paleontologia XVII. Boletim de Resumos. 157.
Bittencourt and Langer, 2011. Mesozoic dinosaurs from Brazil and their biogeographic implications. Anais da Academia Brasileira de Ciências. 83(1), 23-60.

unnamed possible deinonychosaur (Delcourt and Grillo, 2014)
Campanian-Maastrichtian, Late Cretaceous
Vale do Rio do Peixe Formation, Brazil
Material- (DGM 930-R) (~3 m; ~40 kg) partial dorsal rib, several dorsal rib fragments, partial proximal caudal vertebra (42 mm), incomplete mid caudal centrum (~41 mm), ?ischial fragment, femoral fragment (~273 mm), partial pedal ungual ?I/IV, fragments
Comments- Delcourt and Grillo (2014) referred this specimen to Maniraptora (but not Oviraptorosauria or Alvarezsauridae), and tentatively to Deinonychosauria.
Reference- Delcourt and Grillo, 2014. On maniraptoran material (Dinosauria: Theropoda) from Vale do Rio do Peixe Formation, Bauru Group, Brazil. Revista Brasileira de Paleontologia. 17(3), 307-316.

unnamed Deinonychosauria (Franco-Rosas, 2002)
Turonian-Late Maastrichtian, Late Cretaceous
Adamantina, Marilia and/or Serra da Galga Formations of the Bauru Group, Brazil
Material- teeth
Description- These teeth have long serrations with varied slopes and distal shapes, and slightly pronounced interdenticle slits. They are said to be similar to troodontids and velociraptorines.
Reference- Franco-Rosas, 2002. Methodological parameters for the identification and taxonomic classification of isolated theropodomorph teeth. Anais da Academia Brasileira de Ciencias. 74(2), 367.

undescribed deinonychosaur (Bertini, Santucci and Arruda-Campos, 2001)
Late Maastrichtian, Late Cretaceous
Marilia Formation of the Bauru Group, Brazil
Material- (MPMA-73) tooth
Comments- This was listed as a "dente de teropodomorfo deinonycossauriano", but has not yet been illustrated or described.
Reference- Bertini, Santucci and Arruda-Campos, 2001. Titanossauros (Sauropoda: Saurischia) no Cretaceo Superior continental (Formaceo Marilia, Membro Echapora) de Monte Alto, Estado de São Paulo, e correlacao com formas associadas no Triangulo Mineiro. Geociencias, Sao Paulo. 20(1/2), 93-103.

Jinfengopteryginae Turner, Makovicky and Norell, 2012
Definition- (Jinfengopteryx elegans <- Sinovenator changii, Troodon formosus, Passer domesticus) (Turner, Makovicky and Norell, 2012)
= "Jinfengopteryginae" Turner, 2008
Comments- Turner (2008; later published as Turner et al., 2012) created this clade for Jinfengopteryx, IGM 100/1126 and Almas within Troodontidae. Considering the ease at which Jinfengopteryx moves in Hartman et al.'s (2019) maniraptoromorph analysis, this was probably not the best genus to use as an internal specifier. Currently the most parsimonious place for it in Troodontidae is sister to Sinovenator, making the clade limited to Jinfengopteryx itself in that case or when it is a basal deinonychosaur.
References- Turner, 2008. Phylogenetic relationships of paravian Theropods. PhD Thesis. Columbia University. 666 pp.
Turner, Makovicky and Norell, 2012. A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American Museum of Natural History. 371, 1-206.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Jinfengopteryx Ji, Ji, Lu, You, Chen, Liu and Liu, 2005
J. elegans Ji, Ji, Lu, You, Chen, Liu and Liu, 2005
Early Aptian, Early Cretaceous
Qiaotou Member of the Huajiying Formation, Hebei, China
Holotype- (CAGS-IG-04-0801) (548 mm) skull (~68 mm), sclerotic plates, mandible, hyoids, twelve cervical vertebrae, cervical ribs, eleven dorsal vertebrae, dorsal ribs, gastralia, twenty-four caudal vertebrae (273 mm), chevrons, scapulae (47.09 mm), coracoid, furculae, humeri (49.22 mm), radii (42.44 mm), ulnae (43.31 mm), scapholunare, semilunate carpal, metacarpal I (8.77 mm), phalanx I-1 (18.83 mm), manual ungual I (17.75 mm), metacarpal II (21.37 mm), phalanx II-1 (15.26 mm), phalanx II-2 (21.07 mm), manual ungual II (17.32 mm), metacarpal III (~21 mm), phalanx III-1+III-2 (10 mm), phalanx III-3 (12.95 mm), manual ungual III (~14 mm), partial ilium (~49 mm), pubes, partial ischium, femora (70.32 mm), tibiae (100.5 mm), fibula (98.75 mm), proximal tarsus, metatarsus (~59 mm), pedal digit II, pedal digit III, pedal digit IV, feathers, gastroliths/eggs/seeds
Comments- Jin et al. (2008) reassign Jinfengopteryx's horizon to the Qiaotou Member of the Huajiying Formation, as opposed to the Qiaotau Formation which was stated in Ji et al. (2005). Ji et al.'s labeled "pterygoid" looks to be a parasphenoid rostrum, the "squamosal" part of the parietal. Turner (2008) redescribed the skull in his thesis.
Though Ji et al. (2005) assign it to the Archaeopterygidae, I first noted a resemblence to troodontids (Mortimer, DML 2005). Xu and Norell (2006) stated Jinfengopteryx was a possible troodontid based on "general body plan" and several undisclosed dental features. It has been more recently placed in basal Troodontidae (Brusatte et al., 2014; Lee et al., 2014) or basal Paraves (Foth et al., 2014). Hartman et al. (2019) found an unstable position in Troodontidae further from Troodon than Sinusonasus, but one step could move it to basal Deinonychosauria, where later alterations of the matrix placed it. Three steps move it to Archaeopterygidae, while 4 steps move it to basal Paraves.
References- Ji, Ji, Lu, You, Chen, Liu and Liu, 2005. First avialan bird from China (Jinfengopteryx elegans gen. et sp. nov.). Geological Bulletin of China. 24(3), 197-205.
Mortimer, DML 2005. https://web.archive.org/web/20190918121926/http://dml.cmnh.org/2005Mar/msg00372.html
Xu and Norell, 2006. Non-avian dinosaur fossils from the Lower Cretaceous Jehol Group of western Liaoning, China. Geological Journal. 41(3-4), 419-437.
Ji and Ji, 2007. Jinfengopteryx compared to Archaeopteryx, with comments on the mosaic evolution of long-tailed avialan birds. Acta Geologica Sinica (English Edition). 81(3), 337-343.
Jin, Zhang, Li, Zhang, Li and Zhou, 2008. On the horizon of Protopteryx and the early vertebrate fossil assemblages of the Jehol Biota. Chinese Science Bulletin. 53(18), 2820-2827.
Turner, 2008. Phylogenetic relationships of paravian Theropods. PhD Thesis. Columbia University. 666 pp.
Brusatte, Lloyd, Wang and Norell, 2014. Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition. Current Biology. 24(20), 2386-2392.
Foth, Tischlinger and Rauhut, 2014. New specimen of Archaeopteryx provides insights into the evolution of pennaceous feathers. Nature. 511, 79-82.
Lee, Cau, Naish and Dyke, 2014. Sustained miniaturization and anatomical innovation in the dinosaurian ancestors of birds. Science. 345(6196), 562-566.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

unnamed clade (Archaeopteryx lithographica + Dromaeosaurus albertensis)

Imperobator Ely and Case, 2019
I. antarcticus Ely and Case, 2019
Early Maastrichtian, Late Cretaceous
Upper Cape Lamb Member of the Snow Hill Island Formation, James Ross Island, Antarctica
Holotype- (UCMP 276000) (~3-4 m) premaxillary, maxillary and/or dentary fragments, more than two teeth, caudal vertebra, distal tibia (~60 mm trans), (?)tibial fragment, distal fibulae fused to calcanea, medial astragalus, distal tarsal III, metatarsal I (?), pedal ungual I (?), partial metatarsals II, proximal phalanx II-1, partial pedal ungual II, partial metatarsals III, proximal phalanx III-1, distal phalanx III-1, fragmentary phalanx ?III-?, partial metatarsal IV, phalanx IV-1 (~61 mm), fragmentary phalanx ?IV-?, fragmentary pedal ungual IV, metatarsal V (?), pedal elements
....(AMNH FARB 30894) fragmentary (?)cranial elements, partial tooth, partial pedal ungual, several fragments (Lamanna, Case, Roberts, Arbour, Ely, Salisbury, Clarke, Malinzak, West and O'Connor, 2019)
Comments- This was discovered in December 2003 and first reported by Martin and Case (2005) who stated it was a theropod where "the foot structure seems very primitive for a carnivorous dinosaur existing at the end of the Mesozoic", which "does not appear to be related to North American dinosaurs" and instead "appears to be a primitive holdover of the original Gondwanan dinosaur assemblage." Case et al. (2007) described the specimen, placing it in Dromaeosauridae and stating it "more closely resembles Early Cretaceous dromaeosaurs such as Deinonychus and Utahraptor rather than contemporaneous dromaeosaurids, Velociraptor and Dromaeosaurus or regional close (i.e. South American) species like Neuquenraptor ... or Buitreraptor" and "may in fact be a latest Cretaceous remnant of the Early Cretaceous, cosmopolitan, basal stock of dromaeosaurids." While this echos Martin and Case's idea, Deinonychus and Utahraptor have universally been regarded as closer to Velociraptor and Dromaeosaurus than unenlagiines. Their reasons for placing it basally are "the juxtaposition of the ascending process of the astragalus and the anterior distal tibia without a well-defined fossa on the tibia" which is true for almost all pennaraptorans and "the incipient ginglymoidal MtII/digit II joint" which is indeed unlike dromaeosaurids and unenlagiines, as also noted by Turner et al. (2012) who thus assigned it to Deinonychosauria incertae sedis. Ely and Case (2016) recovered the taxon as the most basal deinonychosaur, sister to troodontids plus dromaeosaurids, in an unpublished analysis. Ely and Case (2019) later officially described and named the specimen, including it in Gianechini et al.'s TWiG analysis where it fell out in Paraves in a polytomy with eudromaeosaurian and anchiornithine OTUs. While the authors seem to favor a basal position as in their 2016 abstract, their analyses suggests an anchiornithine troodontid or eudromaeosaurian dromaeosaurid placement are about equally supported. Lamanna et al. (2019) state "Several of the present authors are currently undertaking a comprehensive reassessment of the morphology and phylogenetic rel ationships of Imperobator that will include a description of all known material of this taxon." Entering data from Ely and Case (2019) into the Hartman et al. maniraptoromorph analysis indicates a deinonychosaurian placement more derived than Jinfengopteryx and outside Unenlagiinae and Troodontidae plus Dromaeosauridae.
The materials list has been inconsistent between publications, with Case et al. describing "two teeth that were preserved in a fragment of concretion", Ely and Case (2019) mentioning no cranial material, but Lammana et al. (2019) reporting Case and Malinzak relocated "additional material pertaining to UCMP 276000 at facilities of Eastern Washington University and the South Dakota School of Mines and
Technology, respectively, including skull fragments (probably belonging to at least the premaxilla, maxilla, and/or dentary), a caudal vertebra, and additional teeth and pedal elements", similar to Lammana et al. (2017)'s statement "undescribed craniodental fragments of this theropod individual collected during [2003], initially thought missing, were recently relocated in the collections of the South Dakota School of Mines and Technology." Case et al. state "the left tibia is the most complete of the two tibia fragments" but Ely and Case state "only the distal left tibia is preserved." Ely and Case state "potential material from digit I may be present (Fig. 7D). It is distinguished by what may be a prominent flexor heel on the proximoventral surface, morphologically similar to that of the dromaeosaurid (avialan?) Balaur bondoc (Csiki et al. 2010)", implying a pedal ungual I, but 7D seems to be the proximal half of a non-ungual phalanx positioned as III-1 in Case et al.. In the materials list, Ely and Case also state "material from metatarsal I, and even metatarsal V may be preserved", but we get no description or illustration of these. While the illustrated and described pedal material is from the left pes, Ely and Case state "only a few fragments from the right pes" are preserved, of which the only elements specified in either paper are "distal ends of metatarsals II and III" by Case et al.. Note in Case et al.'s photo of the left pes, distal metatarsal IV and phalanx IV-I figured by Ely and Case are missing, but three small fragments positioned as one part of digit III and two parts of digit IV are shown by Case et al. but not mentioned by Ely and Case except perhaps when they say "a small portion of the ungual [IV?] is also present."
Lamanna et al. (2017) report "a partial tooth, possible craniodental fragments, and part of a pedal ungual" were discovered at the type locality in 2011 or 2016, belonging to the type individual. Lamanna et al. (2019) confirms these were found in both years, "including a tooth and several bone fragments (AMNH FARB 30894), a partial pedal ungual, and fragmentary putative cranial remains."
References- Martin and Case, 2005. Fossil hunting in Antarctica. Geotimes. February 2005, 18-21.
Case, Martin and Reguero, 2007. A dromaeosaur from the Maastrichtian of James Ross Island and the Late Cretaceous Antarctic dinosaur fauna. In Cooper and Raymond (eds.). Online Proceedings of the 10th ISAES X. USGS Open-File Report 2007-1047, Short Research Paper 083, 4 pp.
Turner, Makovicky and Norell, 2012. A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American Museum of Natural History. 371, 1-206.
Ely and Case, 2016. A basal deinonychosaur from the Early Maastrichtian, Antarctic peninsula and the biostratigraphy of the latest Cretaceous dinosaur fauna of Antarctica. Journal of Vertebrate Paleontology. Program and Abstracts 2016, 130.
Lamanna, O'Connor, Salisbury, Gorscak, Clarke, MacPhee, Roberts, Malinzak, Ely and Case, 2017. New material of non-avian dinosaurs from the Late Cretaceous of James Ross Island, Antarctica. Journal of Vertebrate Paleontology. Program and Abstracts 2017, 147.
Ely and Case, 2019. Phylogeny of a new gigantic paravian (Theropoda; Coelurosauria; Maniraptora) from the Upper Cretaceous of James Ross Island, Antarctica. Cretaceous Research. 101, 1-16.
Lamanna, Case, Roberts, Arbour, Ely, Salisbury, Clarke, Malinzak, West and O'Connor, 2019. Late Cretaceous non-avian dinosaurs from the James Ross Basin, Antarctica: Description of new material, updated synthesis, biostratigraphy, and paleobiogeography. Advances in Polar Science. 30(3), 228-250.

Archaeopterygidae Huxley, 1871
Definition- (Archaeopteryx lithographica <- Unenlagia comahuensis, Dromaeosaurus albertensis, Troodon formosus, Passer domesticus) (Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019)
Other definitions- (Archaeopteryx lithographica <- Dromaeosaurus albertensis, Passer domesticus) (Xu, You, Du and Han, 2011)
(Archaeopteryx lithographica <- Passer domesticus) (Sereno, online 2005)
= Sauriurae Haeckel, 1866
= Saururae Huxley, 1867
= "Archornithidae" Carus, 1875
= Saururi Vogt, 1879
= Ornithopappi Stejneger, 1885
= Archaeopteryges Furbringer, 1888
= Archaeopterygiformes Furbringer, 1888
= Archornithes Furbringer, 1888
= Saurura Steinmann and Doederlein, 1890
= Archornithiformes Shefeldt, 1903
= Archaeopterygia Schulze, 1905
= Archaeornithidae Petronievics, 1925
= Archaeopterygomorphi Hay, 1930
Ex-archaeopterygids- Several taxa have been referred to Archaeopterygidae or Archaeopteryx itself in the past, but do not belong there. Janensch (1914) first noted an Archaeopteryx-like supposed carpometacarpus (HMN coll.) from the Tendaguru Formation of Tanzania, but this is based on a misreading of Stremme (1916-1919), who was describing differences from Archaeopteryx. This was named Stremmeia by Nopcsa (1930) and reidentified as a salientian tibiofibulare, and while this identification has been doubted by late twentieth century authors, the specimen is also highly dissimilar to maniraptoran elements. Lambrecht (1933) noted a specimen labeled Archaeopteryx "vicensensis" at the Museum zu Vicensa, but found it was a pterosaur after writing Kleinschmidt. Jensen (1981) identified a proximal femur (BYU 2023) from the Morrison Formation as Archaeopteryx, but this is placed as Ornithodesmiformes incertae sedis here. Kessler and Jurcsak (1984) described an incomplete supposed humerus (MTCO 14422) from the Early Cretaceous of Romania as Archaeopteryx sp., but this was reidentified by Dyke et al. (2011) as a long bone of Archosauria indet.. Paul (1988) referred all dromaeosaurids to Archaeopterygidae, which has not been recovered in any phylogenetic analysis. "Proornis" was originally called "the North Korean Archaeopteryx" (e.g. Anonymous, 1994), but is actually a confuciusornithid (Gao et al., 2009). Weigert (1995) described 103 teeth from the Guimarota Formation of Portugal as cf. Archaeopteryx sp., but they may belong to a basal deinonychosaur instead. Protarchaeopteryx was assigned to the family by Ji and Ji (1997) and Paul (2002), but is probably a basal oviraptorosaur. Forster et al. (1998) found Rahonavis and Unenlagia to clade with Archaeopteryx in some most parsimonious trees, but these are now considered members of their own clade Unenlagiidae which is closer to either dromaeosaurids or birds. Rauhut (2002) referred Paronychodon to Archaeopterygidae, but this was based on comparisons to the Guimarota teeth noted above and the genus is here assigned to Troodontidae based on enamel microstructure. Ji et al. (2005) described Jinfengopteryx as being more closely related to Archaeopteryx than to Aves, but is now recognized as a basal troodontid or basal paravian. Xu et al. (2011) recently used a version of Senter's TWiG analysis to refer Xiaotingia to Archaeopterygidae, but the genus has also been placed as a basal troodontid and basal dromaeosaurid.
Sauriurae- Sauriurae was a group first used by Haekel (1866) for Archaeopteryx, who placed modern birds in the Ornithurae instead. This taxonomy was followed for over a century, with hesperornithines and ichthyornithines being added to Ornithurae by later authors. Martin (1983) was the first author to place enantiornithines in Sauriurae, which has been followed near universally by those who doubt the dinosaur-bird relationship. Additional taxa have also been assigned to Sauriurae including Confuciusornis (Hou et al., 1995), Sinosauropteryx (Ji and Ji, 1996), Protarchaeopteryx (Ji and Ji, 1997), Yandangornis (Cai and Zhao, 1999), Caudipteryx (Martin and Czerkas, 2000), Jeholornis (Martin, 2004), Vorona (Kurochkin, 2006), and lately all deinonychosaurs and oviraptorosaurs (Martin, 2004). The group has basically consisted of any non-euornithine birds considered by the authors, with the notable exception of Kurochkin (2006), who places Protoavis and confuciusornithids in Euornithes (his Ornithurae) and views sauriurines as being theropods while euornithurines are not. While there may be some evidence for placing confuciusornithids and enantiornithines in a group exclusive of Aves, phylogenetic analyses are unanimous in rejecting a clade of Archaeopteryx and enantiornithines which excludes Aves.
References- Haekel, 1866. Generelle Morphologie der Organismen: allgemeine Grundzüge der organischen Formen-Wissenschaft, mechanisch begründet durch die von Charles Darwin reformirte Descendenz-Theorie. Berlin: Reimer. 462 pp.
Huxley, 1867. On the classification of birds; and on the taxonomic value of the modifications of certain of the cranial bones observable in that class. Proceedings of the Zoological Society of London. 35, 415-472.
Carus, 1875. Handbuch der Zoologie. Erster Band: Wirbelthiere, Mollusken und Molluskoiden. 894 pp.
Vogt, 1879. L'Archaeopteryx macroura, Un intermediaire entre les oiseaux et les reptiles. La Revue Scientifique. 9(2), 241-248.
Stejneger, 1884. Classification of Birds. Science Record. 2(7), 154-155.
Furbringer, 1888. Untersuchungeb zur Morphologie und Systematik der Vogel. Amsterdam: Holkema. 1751 pp.
Steinmann and Doederlein, 1890. Elemente der paläontologie bearbeitet. Leipzig. 848 pp.
Shufeldt, 1903. On the classification of certain groups of birds. The American Naturalist. 37, 33-64.
Schulze, 1905. Conspectus classium et ordinum animalium. Zeitschrift fur Naturwissenschaften. 77(1904), 371-373.
Janensch, 1914. Ubersicht uber die Wirbeltierfauna der Tendaguru-Schichten. Archiv fur Biontologie. 3, 81-110.
Stremme, 1916-1919. Uber die durch Bandverknocherung hervorgerufene proximale Verschmelzung zweier Mittelhand - oder Mittelfussknochen eines Reptils. Wissenschaftliche Ergebnisse der Tendaguru-Expedition. Archiv fur Biontologie. 4, 143-144.
Petronievics, 1925. Uber die Berliner Archaeornis. Ann. Geol. Peninsule Balkan. 8(1), 1-52.
Hay, 1930. Second bibliography and catalogue of the fossil Vertebrata of North America. Publication 390 of the Carnegie Institute of Washington, Volume 2.
Nopcsa, 1930. Notes on Stegocephalia and Amphibia. Proceedings of the Zoological Society of London. 1930, 979-995.
Lambrecht, 1933. Handbuch der Palaeornithologie. 1024 pp.
Brodkorb, 1963. Catalogue of fossil birds. Part 1 (Archaeopterygiformes through Ardeiformes). Bull. Florida State Mus., Bioi. Sci.. 7, 179-293.
Jensen, 1981. Another look at Archaeopteryx as the worlds oldest bird. Encyclia, The Journal of the Utah Academy of Sciences, Arts, and Letters. 58, 109-128.
Kessler and Jurcsák, 1984. Fossil birds remains in the bauxite from Cornet (Pa¢durea Craiului Mountains, Romania). 75 years of the Laboratory of Paleontology, University of Bucharest, Romania, Special Volume. 129-134.
Paul, 1988. Predatory Dinosaurs of the World. Simon and Schuster Co., New York. 464 pp.
Anonymous, 1994. Korean Pictorial. 1994(2).
Hou, Zhou, Gu and Zhang, 1995. Confuciusornis sanctus, a new Late Jurassic sauriurine bird from China. Chinese Science Bulletin. 40(18), 1545-1551 [in Chinese].
Weigert, 1995. Isolierte Zahne von cf. Archaeopteryx sp. aus dem Oberen Jura der Kohlengrube Guimarota (Portugal). N. Jb., Geol. Palaont. Mh. 9, 562-576.
Ji and Ji, 1996. 中国最早鸟类化石的发现及鸟类的起源. Chinese Geology. 23(10) (total issue 233), 30-33.
Ji and Ji, 1997. 恩错祖鸟(Protarchaeopteryx gen. nov.) - 中国的始祖鸟类亿右. Chinese Geology. 24(3) (total issue 238), 38-41, 49.
Forster, Sampson, Chiappe and Krause, 1998. The theropod ancestry of birds: New evidence from the Late Cretaceous of Madagascar. Science. 279, 1915-1919.
Cai and Zhao, 1999. A long tailed bird from the Late Cretaceous of Zhejiang. Science in China (series D). 42(4), 434-441.
Martin and Czerkas, 2000. The fossil record of feather evolution in the Mesozoic. American Zoologist. 40(4), 687-694.
Paul, 2002. Dinosaurs of the Air. The Johns Hopkins University Press, Baltimore. 460 pp.
Rauhut, 2002. Dinosaur teeth from the Barremian of Una, Province of Cuenca, Spain. Cretaceous Research. 23, 255-263.
Martin, 2004. A basal archosaurian origin for birds. Acta Zoologica Sinica. 50(6), 978-990.
Ji, Ji, Lu, You, Chen, Liu and Liu, 2005. First avialan bird from China (Jinfengopteryx elegans gen. et sp. nov.). Geological Bulletin of China 24(3): 197-205.
Sereno, online 2005. Stem Archosauria - TaxonSearch. http://www.taxonsearch.org/dev/file_home.php [version 1.0, 2005 November 7]
Kurochkin, 2006. Parallel evolution of theropod dinosaurs and birds. Entomological Review. 86(suppl. 1), S45-S58.
Gao, Li, Wei, Pak and Pak, 2009. Early Cretaceous birds and pterosaurs from the Sinuiju series, and geographic extension of the Jehol biota into the Korean peninsula. Journal of the Paleontological Society of Korea. 25(1), 57-61.
Dyke, Benton, Posmosanu and Naish, 2011. Early Cretaceous (Berriasian) birds and pterosaurs from the Cornet bauxite mine, Romania. Palaeontology. 54(1), 79-95.
Xu, You, Du and Han, 2011. An Archaeopteryx-like theropod from China and the origin of Avialae. Nature. 475, 465-470.
Martyniuk, 2012. A Field Guide to Mesozoic Birds and Other Winged Dinosaurs. Vernon, New Jersey. Pan Aves. 189 pp.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Ostromia Foth and Rauhut, 2017
O. crassipes (Meyer, 1857) Foth and Rauhut, 2017
= Pterodactylus crassipes Meyer, 1857
= Rhamphorhynchus crassipes (Meyer, 1857) Meyer, 1857
= Archaeopteryx crassipes (Meyer, 1857) Ostrom, 1972a
= Scaphognathus crassipes (Meyer, 1857) Olshevsky, 1991
= Archaeornis crassipes (Meyer, 1857) Bühler and Bock, 2002
Early Tithonian, Late Jurassic
Solnhofen Formation, Germany
Holotype- (TM 6928; TM 6929; Haarlem specimen; Teyler specimen; fourth specimen of Archaeopteryx; holotype of Pterodactylus crassipes) (350 day old juvenile) three or four posterior dorsal centra (6.5 mm), dorsal rib fragments, gastralia, distal humerus, incomplete radii, incomplete ulnae, semilunate carpal, metacarpal I (10.5 mm), phalanx I-1 (23.1 mm), manual ungual I (9.5 mm), incomplete metacarpal II, distal manual ungual II, incomplete metacarpal III (23.2 mm), distal phalanx III-3, manual ungual III (8.3 mm), manual claw sheaths, distal pubis, distal femora (~54 mm), proximal tibiae (~80 mm), proximal fibula, fibular fragment, phalanx I-1, partial pedal ungual I, distal metatarsal II, phalanges II-1 (one distal), phalanges II-2, pedal unguals II, distal metatarsal III (~48 mm), phalanges III-1, phalanx III-2, phalanx III-3, pedal unguals III (7.8 mm), distal metatarsal IV, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV, two pedal phalanges, remiges
Diagnosis- (after Foth and Rauhut, 2017) longitudinal furrows on both sides of all preserved manual phalanges and at least metacarpal III (also in Anchiornis and Eosinopteryx); differs from Anchiornis and Eosinopteryx in longer metacarpal I (45% of mcIII length vs. 41% and 42%), manual ungual I shorter than metacarpal I, and longer metatarsus (~60% of tibial length vs. 52% and 51%)
Other diagnoses- Meyer (1857) initially identified the specimen as a pterosaur and distinguished it from other known pterosaurs by the shorter metacarpals I-III, longer manual digits I-III, longer metatarsus and smaller unguals.
Comments- Discovered in 1855, Meyer (1857) named TM 6928/6929 Pterodactylus crassipes, finding the manual proportions and ungual size most similar to Dimorphodon (then Pterodactylus macronyx). Due to incompleteness, Meyer wrote "it would not be impossible that Pterodactylus crassipes also represented a Rhamphorynchus, which will decide on the attachment of the head or tail. If the assumption is confirmed, the species would be called Rhamphorynchus crassipes." As ICZN Article 11.5.1 states "A name proposed conditionally for a taxon before 1961 is not to be excluded on that account alone", this is an available name as well. Meyer (1859/1860) described it in more detail and illustrated a slab. The only other author to consider the specimen was Wellnhofer (1970), who believed it to be a rhamphorhynchoid based on "the short metacarpus, the long metatarsus, the shape of the prebubis and the strikingly large claws on the hands and feet." Furthermore, he stated "the comparison of "Pt." crassipes with Scaphognathus crassirostris reveals broad similarities both in size and morphology of individual skeletal elements (prebubis, femur, claws). Although the existing remains of "Pt." crassipes are not sufficient to make a specific association with Scaphognathus crassirostris, both specimens may certainly be considered congeneric" and on page 122 reidentified crassipes as Scaphognathus sp.. While the combination Scaphognathus crassipes could be implied from Wellnhofer's statement, it was not used explicitly until Olshevsky (1991) who listed it without attribution.
Ostrom (1970) identified the specimen as Archaeopteryx cf. lithographica, stating "the present remains are much too fragmentary for positive species identification" before describing it in detail two years later (1972b) as A. lithographica. His in depth study concluded "With the exception of the apparent difference in pubis position, the Teyler specimen does not differ in any other significant way from the London and Solnhofen specimens of Archaeopteryx. The limb elements are slightly more robust and apparently were slightly longer than those of the Berlin specimen. In summary, I see no morphologic evidence to exclude this specimen from the same taxon as the other three." This was problematic because "the specific name crassipes is a senior synonym of lithographica", yet "the species name A. lithographica is well known and firmly established in the zoologic literature. It therefore seems undesirable to suppress that term in favor of the senior subjective synonym." Thus Ostrom (1972a) petitioned the ICZN to "(a) use its plenary powers to suppress the species name crassipes Meyer, 1857, as published in the binomen Pterodactylus crassipes, for purposes of the Law of Priority but not for those of the Law of Homonymy : (b) place the specific name crassipes (as suppressed under the plenary powers in (a) above) on the Official Index of Rejected and Invalid Specific Names in Zoology." Nye (1974) and Eisenmann (1974) wrote Comments to the ICZN arguing that cases of subjective synonymy such as this, the senior synonym should not be completely suppressed in case it is later thought to be a distinct taxon. Ostrom and the ICZN agreed, so that in 1977 Melville issued the narrower Opinion 1070 that "the specific name lithographica von Meyer, 1861, as published in the binomen Archaeopteryx lithographica, is to be given precedence over the specific name crassipes von Meyer, 1857, as published in the binomen Pterodactylus crassipes by any zoologist who believes that the two specific names apply to the same taxon."
Most recently, Foth and Rauhut (2017) reinterpreted crassipes as an anchiornithid based on longitudinally grooved manual elements and pubic curvature, with proportional differences between it and Archaeopteryx, Anchiornis and Eosinopteryx supporting its validity as the new genus Ostromia. They and Hartman et al. (2019) included Ostromia in analyses based on the TWiG and recovered it closest to anchiornithines, Foth and Rauhut in a polytomy with included taxa, and Hartman et al. in a polytomy with Serikornis and other archaeopterygids (including anchiornithines in their topology).
References- Meyer, 1857. Beiträge zur näheren Kenntniss fossiler Reptilien. Neues Jahrbuch für Mineralogie, Geognosie, Geologie und Petrefakten-Kunde. 1857, 532-543.
Meyer, 1859/1860. Zur Falma der Vorwelt. Vierte Abteilung: Reptilien aus dem lithographischen Schiefer des Jura in Deutschland und Frankreich. Frankfurt. 144 pp.
Ostrom, 1970. Archaeopteryx: notice of a 'new' specimen. Science. 170, 537-538.
Wellnhofer, 1970. Die Pterodactyloidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Abhandlung der Bayerischen Akademie der Wissenschaften, Neue Folge. 141, 133 pp.
Ostrom, 1972a. Pterodactylus crassipes Meyer, 1857 (Aves): Proposed suppression under the plenary powers. Z.N.(S.) 1977. Bulletin of Zoological Nomenclature. 29(1), 30-31.
Ostrom, 1972b. Description of the Archaeopteryx specimen in the Teyler Museum, Haarlem. Proceedings Koninklijke Nederlandse Akademie Van Wetenschappen, B. 75, 289-305.
Eisenmann, 1974. Comment on proposal to suppress Pterodactylus crassipes Meyer, 1857 and counter-proposal to recognize Archaeopteryx lithographica Meyer, 1861, and to fix its type-species. Z.N.(S.) 1977. Bulletin of Zoological Nomenclature. 31(3), 114-115.
Nye, 1974. Comment on: (B)--Proposed supression of Pterodactylus crassipes Meyer (Aves). Z.N.(S.) 1977. Bulletin of Zoological Nomenclature. 30(3/4), 140-141.
Melville, 1977. Opinion 1070. Conservation of Archaeopteryx lithographica von Meyer, 1861 (Aves). Bulletin of Zoological Nomenclature. 33(3/4), 165-166.
Olshevsky, 1991. A Revision of the Parainfraclass Archosauria Cope, 1869, Excluding the Advanced Crocodylia. Mesozoic Meanderings. 2, 196 pp.
Bühler and Bock, 2002. Zur Archaeopteryx-Nomenklatur: Mißverständnisse und Lösung. Journal für Ornithologie. 143, 269-286.
Wellnhofer, 2009. Archaeopteryx: The Icon of Evolution. Verlag Dr. Friedrich Pfeil. 208 pp.
Foth and Rauhut, 2017. Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs. BMC Evolutionary Biology. 17:236.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Serikornis Lefèvre, Cau, Cincotta, Hu, Chinsamy, Escuillié and Godefroit, 2017
S. sungei Lefèvre, Cau, Cincotta, Hu, Chinsamy, Escuillié and Godefroit, 2017
Oxfordian, Late Jurassic
Daxishan, Tiaojishan Formation, Liaoning, China
Holotype- (PMOL-AB00200) (490 mm subadult) incomplete skull, incomplete mandibles, hyoids, nine cervical vertebrae (anterior 8.1, posterior 9.9 mm), cervical ribs, six dorsal vertebrae (anterior 6.7, posterior 6.6 mm), dorsal ribs, synsacrum, twenty-seven caudal vertebrae (proximal 7.7, mid 13, distal 10.8 mm), chevrons, scapula (37.8 mm), coracoids, furcula, humeri (one incomplete; 60.7 mm), radii (one incomplete; 50.5 mm), ulnae (one incomplete; 50.8 mm), semilunate carpal, metacarpals I (12 mm), phalanges I-1 (one incomplete; 27.5 mm), manual ungual I (17 mm), metacarpals II (one incomplete; 32 mm), phalanges II-1 (20 mm), phalanges II-2 (one proximal; 23.5 mm), manual unguals II (19 mm), metacarpals III (one incomplete; 30 mm), phalanx III-1 (7.5 mm), phalanx III-2 (6.5 mm), phalanges III-3 (16 mm), manual unguals III (one proximal; 12.7 mm), ilium (33 mm), distal pubes (63 mm), ischia (~16 mm), femora (67.4 mm), tibiae (tibiotarsus 95.2 mm), fibulae, proximal tarsals, metatarsals I (8.5 mm), phalanges I-1 (9 mm), pedal unguals I (3 mm), metatarsals II (48.5 mm), phalanges II-1 (9 mm), phalanges II-2 (11 mm), pedal unguals II (13 mm), metatarsals III (48.5 mm), phalanges III-1 (12 mm), phalanges III-2 (10 mm), phalanges III-3 (10 mm), pedal ungual III (5.5 mm), metatarsals IV (53 mm), phalanges IV-1 (9 mm), phalanges IV-2 (8 mm), phalanges IV-3 (6 mm), phalanges IV-4 (7 mm), pedal unguals IV (8 mm), metatarsals V (15.5 mm), body feathers, remiges, metatarsal remiges
Diagnosis- (after Lefèvre et al., 2017) four anterior maxillary teeth twice as long as the others; distal end of posteroventral coracoid process thicker than proximal part to form a rounded bump; distal tip of ischium narrow and strongly deflected dorsally to form a hook.
Other diagnoses- Lefèvre et al. (2017) listed "coracoid tuber well-developed and laterally projected from the lateral margin of the coracoid and forming a subglenoid shelf along the caudoventral margin of the bone" as diagnostic compared to Anchiornis, but this is due to perspective and so is true in Anchiornis specimens with more posteriorly exposed coracoids (e.g. BMNHC Ph 822). The "smooth ventral side of coracoid devoid of small pits" is primitive compared to Anchiornis.
Comments- The holotype is one of several paravian specimens acquired by the YFGP from a fossil dealer prior to June 2012. It was labeled YFGP-T5201 in the poster of Brougham (2013, online), which is probably a mistake (see entry for YFGP-T5201).
Lefèvre et al. (2017) assigned a subadult stage to the holotype based on a mix of juvenile ("bone extremities are rough in appearance"; "an uneven periosteal surface which indicates that periosteal growth was still occurring at the time of death") and adult (completely fused sacral vertebrae; completely fused caudal neurocentral sutures) features.
Brougham (2013, online) recovered the specimen in a clade with Aurornis and Eosinopteryx using Turner's dromaeosaurid and Xu's Xiaotingia TWiG matrices and Cau's Aurornis matrix. Lefèvre et al. (2017) used a version of Cau's matrix to recover this as a basal paravian sister to Eosinopteryx, in a clade with Aurornis and Pedopenna. Hartman et al. (2019) found it to be the most basal archaeopterygid using a composite TWiG analysis.
References- Brougham, 2013. Multi-matrix analysis of new Late Jurassic feathered theropods from China supports troodontid-avialan clade. Symposium on Vertebrate Palaeontology and Comparative Anatomy, Programme and Abstracts. 49.
Brougham, 2013 online. https://www.researchgate.net/publication/280728942_SVPCA_Poster
Lefèvre, Cau, Cincotta, Hu, Chinsamy, Escuillié and Godefroit, 2017. A new Jurassic theropod from China documents a transitional step in the macrostructure of feathers. The Science of Nature. 104:74.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247.

Fujianvenator Xu, Wang, Chen, Dong, Lin, Xu, Tang, You, Zhou, Wang, He, Li, Zhang and Zhou, 2023
F. prodigiosus Xu, Wang, Chen, Dong, Lin, Xu, Tang, You, Zhou, Wang, He, Li, Zhang and Zhou, 2023
= Fujianvenator "rapidus" Xu, Wang, Chen, Dong, Lin, Xu, Tang, You, Zhou, Wang, He, Li, Zhang and Zhou, 2023
Etymologies- "'Fujian' (Mandarin), referring to Fujian Province, where the holotype was discovered; 'venator', hunter (Latin); 'prodigiosus', bizarre (Latin), referring to the odd hindlimb morphology preserved in this species." The apparent early species name "rapidus" is no doubt from Latin rapidus "quick", as the authors state "Fujianvenator was well adapted for terrestrial locomotion and is likely to have been capable of running at a high speed."
Late Kimmeridgian-Early Tithonian, Late Jurassic
Nanyuan Formation, Yangyuan Village, Zhenghe County, Nanping City, Fujian, China
Holotype- (IVPP V31985) (641 g using Benson et al. 2018; subadult) tenth cervical vertebra, first dorsal vertebra, second dorsal vertebra, third dorsal vertebra, fourth dorsal vertebra, fifth dorsal vertebra, sixth dorsal vertebra, seventh dorsal vertebra, eighth dorsal vertebra, ninth dorsal vertebra, tenth dorsal vertebra (~9.0 mm), eleventh dorsal vertebra, twelfth dorsal vertebra (~10.1 mm), thirteenth dorsal vertebra, dorsal ribs, gastralia, penultimate ?sacral fragment, ?last ?sacral or ?first ?caudal centrum (~10 mm), first caudal neural arch, second caudal vertebra (~9.3 mm), third caudal vertebra (~10.6 mm), fourth caudal vertebra (~12.3 mm), fifth caudal vertebra (~14.9 mm), sixth caudal vertebra (~14 mm), anterior seventh caudal vertebra, second-sixth chevrons, scapulae (30.5 mm), distal right ?coracoid fragment, sternum (~45 mm), humeri (76.2 mm), radii (64.9 mm), ulnae (65.7 mm), semilunate carpals, carpal fragments, metacarpals I (8.4 mm), phalanges I-1 (36.6 mm), manual unguals I (18.4 mm), metacarpals II (34.0 mm), phalanges II-1 (24.2 mm), left phalanx II-2 (19.5 mm), left manual ungual II (16.5 mm), metacarpals III (31.6 mm), phalanges III-1 (5.9 mm), phalanges III-2 (5.1 mm), phalanges III-3 (19.2 mm), right manual ungual III (14.5 mm), manual claw sheaths, ilia (32.0 mm), pubes (46.1 mm), ischia (15.8 mm), femora (55.1 mm), tibiae (110.5 mm), fibulae, astragalocalcanea (~7.8 mm trans), left metatarsal I (10.8 mm), left phalanx I-1, metatarsals II (58.1 mm), proximal right metatarsal III, left metatarsal III (59.3 mm), left phalanx III-1 (~12 mm), proximal right metatarsal IV, left metatarsal IV (54.8 mm), left phalanx IV-1 (~9.8 mm), two incomplete pedal phalanges (~6.5, ~7 mm), metatarsals V (8.6 mm)
Diagnosis- (after Xu et al, 2023; autapomorphies only) metacarpals I and II have asymmetric ginglymoid distal articulations with enlarged medial condyles; short ischium that has distally located obturator process and distodorsal process; tibia twice as long as femur.
Comments- The holotype was discovered between October 14 and November 14 2022. Xu et al.'s (2023) reporting summary states "The holotype of Fujianvenator rapidus (IVPP V31985) was discovered in Daxi Basin near Yangyuan Village, Zhenghe Country, Nanping City, Fujian Province, Southeast China" three times, making this a likely early name for the species. Note the entire specimen is broken between slab and counterslab so that elements are preserved in section, and often have broken or confluent edges. While Xu et al. only state the trunk "consists of 10-12 articulated vertebrae", the counterslab's presacral column extends about three vertebrae anterior to thie eleven preserved on the slab although no morphologies are visible. This makes the cervicodorsal transition unknowable, but the right pectoral girdle is placed properly for a series of thirteen dorsals, and an elongate rib below the 'third' dorsal on the slab indicates at least eleven were present. While the interpreted figures show two structures labeled "?sv" which have the outlines of two series of sacrals with potential anterior sacrals shown below the right ilium, only the last element of the more ventral 'series' is obvious in the specimen (slab side) with an adjacent fragment potentially being part of the previous vertebra. The first caudal centrum as shown articulating with the rest of the tail does not seem to be present, but the slab shows what may be a first caudal neural arch just dorsal to this position. Indeed, while the authors say "Considering the articulated vertebral column, the proximity of the ilium and caudal vertebrae and the position of two possible caudalmost sacral vertebrae, one or two additional vertebrae might have been present anterior to those eight centra", it seems more natural to suggest the supposed last sacral centrum belongs to the apparent first caudal neural arch directly above it. While the text claims the "tail preserves only eight anterior vertebrae with recognizable features", Figure 1a shows the slab preserves nothing past the anteroventral corner of caudal six, and Figure 2a-b shows nothing identifiable past the anterior half of caudal seven in the counterslab. No structure is present where the figure labels the right coracoid (area only preserved on the counterslab), but a piece just proximal to the right humerus may be its distal portion, or may be part of the right humeral head. The supposed right scapholunare ("radiale") is considered here more similar to a semilunate carpal in shape, while the supposed right pisiform ("ulnare") is either fragmented or partially covered by sediment and if the latter is more likely to be the actual semilunate based on its position and the carpals of related taxa. The medial and lateral condyles of the right astragalocalcaneum are switched in the figures. Contra the interpretive drawing that shows two small pedal phalanges in side view next to pedal phalanx III-1, this instead appears to be the distal end of right metatarsal II in dorsal view, being continuous with the proximal portion and the correct length. Xu et al. state "The specimen is not skeletally mature, given the unfused metacarpals and tibiotarsus. On the basis of the closed neurocentral sutures of the dorsal vertebrae, the fused astragalus and calcaneum and the ossified sternum, we interpret IVPP V31985 as a subadult."
Xu et al. (2023) used a version of Brusatte's TWiG analysis to recover Fujianvenator as an anchiornithid in a polytomy with other members. When added to my maniraptoromorph matrix from Hartman et al. 2019, it resolves sister to Serikornis in Archaeopterygidae.
Reference- Xu, Wang, Chen, Dong, Lin, Xu, Tang, You, Zhou, Wang, He, Li, Zhang and Zhou, 2023. A new avialan theropod from an emerging Jurassic terrestrial fauna. Nature. 621, 336-343.

Pedopenna Xu and Zhang, 2005
P. daohugouensis Xu and Zhang, 2005
Bathonian-Callovian, Middle Jurassic
Daohugou, Haifanggou Formation, Inner Mongolia, China
Holotype- (IVPP V12721) (<1 m) distal tibiotarsus, distal fibula, metatarsal I, phalanx I-1 (8.6 mm), pedal ungual I (~7.6 mm), metatarsal II (57.6 mm), phalanx II-1 (11.6 mm), phalanx II-2 (14.2 mm), pedal ungual II (~13 mm), metatarsal III (~57.8 mm), phalanx III-1 (~18 mm), phalanx III-2 (~11.3 mm), phalanx III-3 (~11.3 mm), pedal ungual III (10.1 mm), metatarsal IV (57.4 mm), phalanx IV-1 (11.3 mm), phalanx IV-2 (9.9 mm), phalanx IV-3 (6.2 mm), metatarsal V (14.1 mm), feathers, scale impressions, pedal claw sheath
Diagnosis- (from Xu and Zhang, 2005) very slender pedal phalanx I-1 (length/mid-shaft-diameter ratio about 7.2).
Comments- Recovered in 2002 from the Daohugou beds, which have more recently been assigned to the Haifanggou Formation (e.g. Xu et al., 2016).
Xu and Zhang (2005) recovered Pedopenna as a paravian in a trichotomy with avialans and deinonychosaurs using a version of the TWiG matrix. More recently, Brusatte et al. (2014) found it to be a scansoriopterygid, while Foth et al. (2014) found it to be a basal avialan in a clade with Anchiornis and Eosinopteryx. Hartman et al. (2019) recovered it as a scansoriopterygid, but only one step moved it to Archaeopterygidae.
References- Xu and Zhang, 2005. A new maniraptoran dinosaur from China with long feathers on the metatarsus. Naturwissenschaften. 92, 173-177.
Brusatte, Lloyd, Wang and Norell, 2014. Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition. Current Biology. 24(20), 2386-2392.
Foth, Tischlinger and Rauhut, 2014. New specimen of Archaeopteryx provides insights into the evolution of pennaceous feathers. Nature. 511, 79-82.
Xu, Zhou, Sullivan, Wang and Ren, 2016. An updated review of the Middle-Late Jurassic Yanliao Biota: Chronology, taphonomy, paleontology and paleoecology. Acta Geologica Sinica. 90(6), 2229-2243.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Caihong Hu, Clarke, Eliason, Qiu, Li, Shawkey, Zhao, D'Alba, Jiang and Xu, 2018
C. juji Hu, Clarke, Eliason, Qiu, Li, Shawkey, Zhao, D'Alba, Jiang and Xu, 2018
Oxfordian, Late Jurassic
Gangou (= Zhuanshanzi), Tiaojishan Formation, Hebei, China
Holotype- (PMOL-B00175) (400 mm, ~475 g, adult) skull (~67.6 mm), mandibles, hyoids, (cervical series ~72 mm) about ten cervical vertebrae, cervical ribs, (dorsal series ~87.8 mm) about twelve dorsal vertebrae, dorsal ribs, gastralia, five sacral vertebrae (~31.5 mm), (caudal series ~178 mm) first to twenty-sixth caudal vertebrae, chevrons, scapulae, coracoids, furcula, humeri (one proximal; 42.1 mm), radii (one distal), ulnae (one distal; 47.2 mm), metacarpals I (8.6, 9.3 mm), phalanges I-1 (18.2, 21.8 mm), manual ungual I (7.5 mm), metacarpals II (23.2, 23.7 mm), phalanges II-1 (11.6, 11.8 mm), phalanges II-2 (19.9, 20 mm), manual ungual II (10.6 mm), metacarpals III (23.2, 23.5 mm), phalanges III-1 (5.4, 5.9 mm), phalanges III-2 (5.7, 5.8 mm), phalanges III-3 (13.3, 13 mm), manual unguals III (7.8, 7.8 mm), partial ilium (31 mm), pubes (54.9 mm), ischium (20.5 mm), femora (70.9 mm), tibiae (82.8, 81.6 mm), proximal tarsals, metatarsal I (5.5 mm), phalanx I-1 (4.2 mm), pedal ungual I (4.4 mm), metatarsals II (47.3, 47.6 mm), phalanges II-1 (~8, 8.7 mm), phalanges II-2 (9.6 mm), pedal unguals II (10.5 mm), metatarsal III (49 mm), phalanges III-1 (12.2 mm), phalanges III-2 (8.4, 8 mm), phalanges III-3 (~8.9, 8.9 mm), pedal unguals III, metatarsal IV (46.6 mm), phalanx IV-1 (8.2 mm), phalanx IV-2 (7.2 mm), phalanx IV-3 (5.7 mm), phalanges IV-4 (6.4, 6.2 mm), pedal unguals IV (8.3 mm), body feathers, remiges (~97 mm), metatarsal remiges (~31 mm), retrices (112 mm)
Diagnosis- (after Hu et al., 2018) accessory fenestra posteroventral to promaxillary fenestra; lacrimal with prominent dorsolaterally oriented crests; robust dentary with anterior tip dorsoventrally
deeper than its midsection; short ilium (<50% of the femoral length).
Comments- Collected by a farmer, the holotype was acquired by the PMOL in February 2014.
Hu et al. (2018) recovered Caihong as an anchiornithid closest to Xiaotingia in Xu et al.'s 2011 TWiG analysis, and an anchiornithid in Brusatte's TWiG analysis. Hartman et al. (2019) recovered it as a basal archaeopterygid (including 'anchiornithines'), but found it moved to a basal dromaeosaurid in two steps.
References- Hu, Clarke, Eliason, Qiu, Li, Shawkey, Zhao, D'Alba, Jiang and Xu, 2018. A bony-crested Jurassic dinosaur with evidence of iridescent plumage highlights complexity in early paravian evolution. Nature Communications. 9, 217.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Anchiornithinae Xu, Zhou, Sullivan, Wang and Ren, 2016
Definition- (Anchiornis huxleyi <- Archaeopteryx lithographica, Troodon formosus, Epidexipteryx hui, Gallus gallus, Dromaeosaurus albertensis, Unenlagia comahuensis) (Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019; modified after Xu, Zhou, Sullivan, Wang and Ren, 2016)
= Anchiornithidae Xu, Zhou, Sullivan, Wang and Ren, 2016 vide Foth and Rauhut, 2017
Definition- (Anchiornis huxleyi <- Passer domesticus, Archaeopteryx lithographica, Dromaeosaurus albertensis, Troodon formosus, Oviraptor philoceratops) (Foth and Rauhut, 2017)
Other definitions- (Anchiornis huxleyi <- Vultur gryphus, Archaeopteryx lithographica, Dromaeosaurus albertensis, Saurornithoides mongoliensis, Unenlagia comahuensis, Epidendrosaurus ninchengensis) (Cau, Beyrand, Voeten, Fernandez, Tafforeau, Stein, Barsbold, Tsogtbaatar, Currie and Godefroit, 2017)
= Anchiornithidae sensu Cau, Beyrand, Voeten, Fernandez, Tafforeau, Stein, Barsbold, Tsogtbaatar, Currie and Godefroit, 2017
Definition- (Anchiornis huxleyi <- Vultur gryphus, Archaeopteryx lithographica, Dromaeosaurus albertensis, Saurornithoides mongoliensis, Unenlagia comahuensis, Epidendrosaurus ninchengensis)
References- Xu, Zhou, Sullivan, Wang and Ren, 2016. An updated review of the Middle-Late Jurassic Yanliao Biota: Chronology, taphonomy, paleontology and paleoecology. Acta Geologica Sinica. 90(6), 2229-2243.
Cau, Beyrand, Voeten, Fernandez, Tafforeau, Stein, Barsbold, Tsogtbaatar, Currie and Godefroit, 2017. Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs. Nature. 552, 395-399.
Foth and Rauhut, 2017. Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs. BMC Evolutionary Biology. 17:236.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247
Anchiornis Xu, Zhao, Norell, Sullivan, Hone, Erickson, Wang, Han and Guo, 2008
A. huxleyi Xu, Zhao, Norell, Sullivan, Hone, Erickson, Wang, Han and Guo, 2008
Oxfordian, Late Jurassic
Tiaojishan Formation, Liaoning, China
Holotype- (IVPP V14378) (~340 mm; 110 g; subadult or young adult) posterior cervical vertebrae (eighth cervical 5 mm), thirteen dorsal vertebrae (second dorsal 4.3 mm, seventh dorsal 4.8 mm, eleventh dorsal 5.1 mm), nineteen dorsal ribs, sacrum, seventeen caudal vertebrae (first caudal 2.8 mm, tenth caudal 7.4 mm), chevrons, scapulae (26.8 mm), coracoids, furcula, humeri (41.5 mm), radius, ulna (37.1 mm), scapholunare, distal carpal III, metacarpal I, carpometacarpus, phalanx I-1, manual ungual I, phalanx II-1, phalanx II-2, manual ungual II, phalanx III-1, phalanx III-2, phalanx III-3, manual ungual III, incomplete ilium (~26.2 mm), partial ischium, femora (43.2 mm), tibiae (67.8 mm), metatarsal I, metatarsals II, phalanges II-1, phalanges II-2, pedal unguals II, metatarsals III, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, metatarsals IV, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, metatarsals V, pedal claw sheaths, feathers
Referred- (41HIII 0404) (574 mm, adult) partial skull, mandibles (52.7 mm), hyoids, basihyoid, six cervical vertebrae, cervical ribs, anterior dorsal vertebrae, sixth to thirteenth dorsal vertebrae, dorsal ribs, gastralia, (caudal series 290.6 mm) first caudal vertebra (6.1 mm), incomplete second caudal vertebra (6.5 mm), incomplete third caudal vertebra (7.5 mm), partial fourth caudal vertebra, partial fifth caudal vertebra, sixth caudal vertebra (9.7 mm), seventh caudal vertebra (10.8 mm), eighth caudal vertebra (11.3 mm), ninth caudal vertebra (11.4 mm), tenth caudal vertebra (11.4 mm), eleventh caudal vertebra (11 mm), twelfth caudal vertebra, thirteenth caudal vertebra, fourteeenth caudal vertebra, fifteenth caudal vertebra (11.6 mm), sixteenth caudal vertebra (11 mm), seventeenth caudal vertebra, eighteenth caudal vertebra (11.3 mm), nineteenth caudal vertebra (11 mm), twentieth caudal vertebra (10.3 mm), twenty-first caudal vertebra (9.9 mm), twenty-second caudal vertebra (9.2 mm), twenty-third caudal vertebra (8.2 mm), twenty-fourth caudal vertebra (7.6 mm), twenty-fifth caudal vertebra (6.9 mm), twenty-sixth caudal vertebra, partial twenty-seventh caudal vertebra, partial twenty-eighth caudal vertebra, distal scapulae, ?coracoid fragment, furcula, humeri (63.2 mm), radii (51 mm), ulnae (52.9, 52.9 mm), scapholunare, semilunate carpal, metacarpal I (11.2 mm), phalanges I-1 (one partial; 24.4, 24.3 mm), manual ungual I (15.9 mm), metacarpals II (30.9 mm), phalanges II-1 (one proximal; 19 mm), phalanx II-2 (24.6 mm), manual unguals II (one incomplete; 16.4, 15.7 mm), metacarpals III (28.7 mm), phalanges III-1 (7.6, 7.7 mm), phalanges III-2 (one fragmentary; 6.8, 7.4 mm), phalanges III-3 (12.8, 13 mm), manual unguals III (13.8 mm), manual claw sheaths, incomplete ilium (36.3 mm), pubes (one partial; 53.7 mm), ischia (20.8 mm), femora (65.6, 66.8 mm), tibiae (92.5 mm), fibulae (90.6 mm), astragali, calcanea, metatarsal I (8.7 mm), phalanx I-1 (6.6 mm), pedal unguals I (6.2 mm), metatarsals II (49.2, 48.3 mm), phalanx II-1 (11.2 mm), phalanges II-2 (11.3 mm), pedal unguals II, metatarsals III (52.8, 49.5 mm), phalanges III-1 (13.4 mm), phalanges III-2 (10.1, 10.8 mm), phalanx III-3 (9.4 mm), pedal ungual III (13 mm), metatarsals IV (52.2, 50.1 mm), phalanges IV-1 (9.8, 9.8 mm), phalanges IV-2 (one proximal; 5.6 mm), phalanx IV-3 (~13.2 mm), phalanx IV-4, pedal ungual IV (12.1 mm), metatarsals V (13.1 mm), body feathers, retrices (Guo, Xu and Jia, 2018)
(41HIII 0415) (375 mm, adult) skull (51.4 mm), mandibles, axis, third to ninth cervical vertebrae, third to thirteenth dorsal vertebrae, dorsal ribs, first to twenty-fourth caudal vertebrae, scapulae (25.7 mm), coracoids, furcula, humeri (43.8, 42.8 mm), radii (36.9, 34.6 mm), ulnae (37.3, 34.6 mm), scapholunare, semilunate carpal, metacarpals I (8.3, 7.9 mm), phalanges I-1 (21.6, 18 mm), manual unguals I (8.2, 8.6 mm), metacarpals II (21.5 mm), phalanges II-1 (12.5 mm), phalanges II-2 (18.6, 19.3 mm), manual unguals II (9.5, 9.6 mm), metacarpal III, phalanx III-1, phalanx III-2 (6.4 mm), phalanx III-3 (10.4 mm), manual ungual III (7.7 mm), fragmentary ilium, ischia (13.6 mm), femora (46.8 mm), tibiotarsi (71.5, 71.2 mm), fibulae, metatarsals I (4.8, 3.9 mm), phalanges I-1 (5.5, 5.7 mm), pedal unguals I (2.7, 3.6 mm), metatarsals II (32.9, 36.2 mm), phalanges II-1 (7.7, 8.6 mm), phalanges II-2 (7.8, 7.8 mm), pedal unguals II (5.8 mm), metatarsals III (35.7, 37.2 mm), phalanges III-1 (9.1 mm), phalanges III-2 (7.6, 7.6 mm), phalanges III-3 (7.2, 6.9 mm), pedal unguals III (6.4, 5.7 mm), metatarsals IV (32.8, 35.9 mm), phalanges IV-1 (5.8, 7.5 mm), phalanges IV-2 (4.4, 5.5 mm), phalanges IV-3 (3.5, 4.9 mm), phalanges IV-4 (2.1, 5.4 mm), pedal ungual IV (4.1 mm), metatarsal V (Guo, Xu and Jia, 2018)
(BMNHC Ph 804) skull (43.5 mm), partial mandibles, hyoid, ten cervical vertebrae, twelve dorsal vertebrae, dorsal ribs, gastralia, synsacrum, thirty-one or thirty-two caudal vertebrae, scapulae (29.1, 29.1 mm), coracoids, furcula, humeri (45.7, 44.5 mm), radii (39.1, 38.2 mm), ulnae (39.8, 38.8 mm), scapholunare, semilunate carpals, metacarpals I, phalanx I-1, manual ungual I, metacarpals II, phalanx II-1 (11.4 mm), phalanx II-2 (18.1 mm), manual ungual II (10.1 mm), metacarpals III, phalanx III-1 (6.9 mm), phalanx III-2 (6.6 mm), phalanx III-3 (9.5 mm), manual ungual III (9 mm), ilium (25.1 mm), pubes (39.2 mm), ischia (~19 mm), femora (50.9 mm), tibiae (tibiotarsi 69.5, 69.1 mm), fibulae, proximal tarsals, metatarsal I, phalanges I-1 (5.3 mm), pedal unguals I (4.2 mm), metatarsals II (39.7 mm), phalanges II-1 (8.7, 8.7 mm), phalanges II-2 (8.3, 7.6 mm), pedal ungual II (9.1 mm), metatarsals III, phalanges III-1 (9.8, 9.7 mm), phalanges III-2 (8, 7.8 mm), phalanges III-3 (7.1, 7 mm), pedal unguals III (7.9, 7.7 mm), metatarsals IV (38.3, 38.3 mm), phalanges IV-1 (7.4, 7.4 mm), phalanges IV-2 (5.2, 5.2 mm), phalanx IV-3 (5.1, 5.2 mm), phalanx IV-4 (4.9, 5.1 mm), pedal unguals IV (6.1, 5 mm), metatarsal V, body feathers, remiges, metatarsal remiges (Pei et al., 2017)
(BMNHC Ph 822) skull (61.2 mm), mandibles, ten cervical vertebrae, cervical ribs, about twelve dorsal vertebrae, dorsal ribs, gastralia, synsacrum, thirty to thirty-one caudal vertebrae, chevrons, scapula (40.8 mm), coracoid, incomplete furcula, humeri (61.8, 64.9 mm), radii (58.9 mm), ulnae (58.9, 60.8 mm), scapholunare, semilunate carpal, metacarpal I (12.6 mm), phalanges I-1 (29.6 mm), manual unguals I (18.6 mm), metacarpals II (36.2 mm), phalanges II-1, phalanges II-2, manual unguals II (20.8 mm), metacarpals III (32.7 mm), phalanges III-1 (8.7 mm), phalanges III-2 (7.2 mm), phalanges III-3 (15.3 mm), manual unguals III (13.5 mm), ilium (34.8 mm), pubes (61.4 mm), ischium, femora (70.5 mm), tibiae (tibiotarsi 108.6, 108 mm), fibulae, proximal tarsals, metatarsal II (57.8 mm), phalanges II-1 (11.2 mm), phalanges II-2 (12.2 mm), pedal unguals II (13.3 mm), metatarsal III (58 mm), phalanges III-1 (15.2 mm), phalanges III-2 (11.2 mm), phalanges III-3 (7.8 mm), pedal unguals III, metatarsal IV (56.1 mm), phalanges IV-1 (11.6 mm), phalanges IV-2 (8.9 mm), phalanges IV-3 (8.4 mm), phalanges IV-4 (7.9 mm), pedal unguals IV (10.8 mm), pedal claw sheaths, body feathers, remiges, metatarsal remiges (Pei et al., 2017)
(BMNHC Ph 823) skull (56 mm), mandibles, few posterior cervical vertebrae, twelve dorsal vertebrae, synsacrum, at least thirty-one caudal vertebrae, chevrons, scapulae (40.1 mm), coracoid, partial furcula, humeri (65.2, 64.5 mm), partial radii, partial ulnae, distal phalanx I-1, manual ungual I, phalanx II-1, phalanges II-2, manual unguals II, distal metacarpal III, phalanx III-1, phalanx III-2, phalanx III-3, manual unguals III, ilia (40.9, 42.3 mm), ischia (22.1 mm), femora (68.7, 67.8 mm), tibiae (tibiotarsi 95.2, 92.1 mm), fibula, proximal tarsals, phalanges I-1 (7.5 mm), pedal unguals I, metatarsals II (49 mm), phalanx II-1 (10.4 mm), phalanx II-2 (8.1 mm), pedal ungual II (13 mm), metatarsals III (51.2 mm), phalanx III-1 (12.8 mm), phalanx III-2 (7.8 mm), phalanx III-3 (11 mm), pedal ungual III (13.2 mm), metatarsals IV (48.5 mm), phalanx IV-2 (8.8 mm), phalanx IV-3 (7.5 mm), phalanx IV-4 (7.2 mm), pedal ungual IV (13.4 mm) (Pei et al., 2017)
(BMNHC Ph 828) skull (38.5 mm), incomplete mandibles, several dorsal vertebrae, three gastralia, partial sacrum, scapulocoracoids (scapula ~23 mm), furcula, humeri (40 mm), radii, ulnae (35.3 mm), scapholunares, semilunate carpals, distal carpal III, metacarpals I (7.8 mm), phalanges I-1, manual unguals I, metacarpals II (20 mm), phalanges II-1, phalanges II-2, manual ungual II, metacarpals III (19.5 mm), phalanx III-1, phalanges III-2, phalanges III-3, manual ungual III, manual claw sheaths, distal femur, tibiae (65.6 mm), astragalus, distal tarsals, metatarsals II, phalanx II-1, phalanx II-2, pedal ungual II, phalanges III-1, phalanges III-2, phalanges III-3, pedal ungual III, metatarsals IV, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal ungual IV, metatarsal V, pedal claw sheaths, body feathers (15-20 mm), remiges (to 62 mm), metatarsal remiges (Li et al., 2010)
(C.0502) (462 mm) skull (62.5 mm), mandibles (52.7 mm), hyoids, (cervical series 62 mm) ten cervical vertebrae, cervical ribs, (dorsal series ~69.6 mm) twelve dorsal vertebrae, dorsal ribs, gastralia, (sacrum ~25.5 mm) five sacral vertebrae, (caudal series 243.1 mm) thirty-three caudal vertebrae (first 4.2, twelfth 10.2, twenty-second 8.9 mm), chevrons, scapula (33.7 mm), coracoids, furcula, humeri (51.3, 51 mm), radii (45, 46.2 mm), ulnae (45.2, 46.4 mm), scapholunares, semilunate carpals, distal carpal III, metacarpals I (10.6, 11 mm), phalanges I-1 (21.3, 21.6 mm), manual unguals I (14.2, 16.3 mm), metacarpals II (26.8, 26.9 mm), phalanges II-1 (16.7, 17.6 mm), phalanges II-2 (20.6, 22.2 mm), manual unguals II (15.1, 17.3 mm), metacarpals III (25.8, 26.1 mm), phalanges III-1 (5, 6.6 mm), phalanges III-2 (6.2, 6.4 mm), phalanges III-3 (12.9, 12.2 mm), manual unguals III (15.1, 13.4 mm), manual claw sheaths, incomplete ilia, pubes (48.9, 49.1 mm), ischia, femora (55.4, 56.4 mm), tibiae (tibiotarsi 81.8, 82 mm), proximal tarsals, metatarsal I, phalanx I-1 (6.5 mm), pedal ungual I (5.2 mm), metatarsals II (45.1, 44.9 mm), phalanges II-1 (10.6, 10.7 mm), phalanges II-2 (10.4, 10.6 mm), pedal unguals II (10.9, 10.3 mm), metatarsals III (48.2, 48.1 mm), phalanges III-1 (11.8, 11.6 mm), phalanges III-2 (9, 9.5 mm), phalanges III-3 (8.6, 8.6 mm), pedal unguals III (11.4, 11.4 mm), metatarsals IV (44.4, 44.4 mm), phalanges IV-1 (9.2, 9.4 mm), phalanges IV-2 (6.9, 6.6 mm), phalanges IV-3 (6.2, 6.3 mm), phalanges IV-4 (6.7, 6.8 mm), pedal unguals IV (8, 10 mm), metatarsals V (10.3, 13.4 mm), pedal claw sheaths, body feathers, remiges, retrices, metatarsal remiges (Jiang, 2011)
(LPM-B00169) skull (63.7 mm), mandibles (53.8 mm), eight cervical vertebrae (series 66.8 mm), thirteen dorsal vertebrae (series 85.4 mm), sixteen dorsal ribs, gastralia, sacrum (31 mm), nineteen caudal vertebrae (first caudal 5.2 mm, thirteenth caudal 14.2 mm, eighteenth caudal 13.5 mm), seventeen chevrons, scapulae (one fragmentary; 45.2 mm) coracoid, furcula, humeri (69 mm), radii (54 mm), ulnae (55.1 mm), scapholunares, pisiforms, semilunate carpals, metacarpals I (12.4 mm), phalanges I-1 (26.2 mm), manual ungual I (15.6 mm), metacarpals II (33.9 mm), phalanges II-1 (21 mm), phalanges II-2 (27 mm), manual unguals II (20.2 mm), metacarpals III (30.5 mm), phalanges III-1 (7.2 mm), phalanges III-2 (8.1 mm), phalanx III-3 (14.2 mm), manual ungual III (13.8 mm), manual claw sheaths, ilia (one partial; 37.4 mm), pubes (61.4 mm), ischium (22.4 mm), femora (66.2 mm), tibiae (106.4 mm), fibula, astragalus, distal tarsal IV, metatarsals I (11.1 mm), pedal ungual I, metatarsals II (51.2 mm), phalanges II-1 (11.5 mm), phalanges II-2 (12.2 mm), pedal unguals II (14.9 mm), metatarsals III (55.2 mm), phalanges III-1 (12.9 mm), phalanges III-2 (11.1 mm), phalanges III-3 (10.5 mm), pedal unguals III (13.7 mm), metatarsals IV (51.9 mm), phalanges IV-1 (10.8 mm), phalanges IV-2 (8.8 mm), phalanges IV-3 (7 mm), phalanges IV-4 (7.6 mm), pedal unguals IV (13.5 mm), metatarsals V (19.2 mm), pedal claw sheaths, body feathers, remiges, metatarsal remiges (Hu et al., 2009)
(LPM coll.) (Hu et al., 2009- page S3)
(PKUP V1068) skull, mandibles (one incomplete), ten cervical vertebrae, twelve dorsal vertebrae, first sacral vertebra, fused second to fourth sacral vertebrae, fifth sacral vertebra, twenty-two caudal vertebrae, scapulae (~34,2 mm), coracoids, furcula, humeri (72.2 mm), radii (52, 52.8 mm), ulnae (59, 58.5 mm), scapholunares, semilunate carpals, metacarpals I (12.4, 12.7 mm), phalanges I-1 (25, 26.1 mm), manual unguals I (21.8 mm), metacarpals II (32.1, 35 mm), phalanges II-1 (18.9, 18 mm), phalanges II-2 (26.8 mm), manual unguals II (20.5 mm), metacarpals III (29.8 mm), phalanges III-1 (7.2 mm), phalanges III-2 (6.9 mm), phalanges III-3 (14.7 mm), manual unguals III (14 mm), partial ilia (42.2, ~48.1 mm), pubes (56.9, 55.2 mm), femora (88.5, 90.5 mm), tibiae (tibiotarsi 112, 117.7 mm), fibulae, proximal tarsals, phalanx I-1, pedal ungual I, metatarsals II (50, 56.2 mm), phalanges II-1 (13 mm), phalanges II-2 (13, 11.5 mm), pedal ungual II, metatarsals III (one incomplete; 51.5, 56.4 mm), phalanges III-1 (15, 15.1 mm), phalanx III-2 (10 mm), phalanx III-3 (11.3 mm), pedal ungual III (16.8 mm), metatarsals IV (one partial; 49.1, 55 mm), phalanges IV-1 (11, 11.5 mm), phalanges IV-2 (9.1 mm), phalanges IV-3, phalanges IV-4, pedal ungual IV (10.2 mm) (Pei et al., 2017)
(STM 0-1) incomplete skeleton including femur (44 mm) and feathers (Zheng et al., 2014)
(STM 0-2) incomplete skeleton including gastralia and femur (70 mm) (Zheng et al., 2014)
(STM 0-3) incomplete skeleton including gastralia, femur (75 mm) and feathers (Zheng et al., 2014)
(STM 0-4) incomplete skeleton including femur (65 mm) and feathers (Zheng et al., 2014)
(STM 0-5) incomplete skeleton including femur (41 mm) and feathers (Zheng et al., 2014)
(STM 0-6) material including gastralia (Zheng et al., 2014)
(STM 0-7) incomplete skeleton including premaxilla, mandible, caudal vertebrae, humerus, radius, ulna, metacarpal II, manual phalanx II-2, manual ungual II, metacarpal III, manual claw sheath, ischium, femur (64 mm), tibia, fibula, metatarsal I, metatarsal II, phalanx II-1, phalanx II-2, pedal ungual II, metatarsal III, phalanx III-1, phalanx III-2, phalanx III-3, metatarsal IV, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, scales and feathers (Zheng et al., 2014)
(STM 0-8) (adult) incomplete skeleton including gastralia, femur (86 mm) and feathers (Zheng et al., 2014)
(STM 0-9) incomplete skeleton including femur (65 mm) and feathers (Zheng et al., 2014)
(STM 0-10) incomplete skeleton including gastralia and femur (47 mm) (Zheng et al., 2014)
(STM 0-11) material including gastralia and feathers (Zheng et al., 2014)
(STM 0-12) incomplete skeleton including gastralia, femur (50 mm) and feathers (Zheng et al., 2014)
(STM 0-13) incomplete skeleton including femur (73.5 mm) (Zheng et al., 2014)
(STM 0-14) incomplete skeleton including gastralia and femur (67 mm) (Zheng et al., 2014)
(STM 0-15) material including gastralia (Zheng et al., 2014)
(STM 0-16) incomplete skeleton including gastralia, femur (50 mm) and feathers (Zheng et al., 2014)
(STM 0-17) incomplete skeleton including gastralia, femur (60 mm) and feathers (Zheng et al., 2014)
(STM 0-18) incomplete skeleton including gastralia, femur (74 mm) and feathers (Zheng et al., 2014)
(STM 0-19) incomplete skeleton including gastralia, femur (68 mm) and feathers (Zheng et al., 2014)
(STM 0-20) incomplete skeleton including gastralia and femur (52 mm) (Zheng et al., 2014)
(STM 0-21) incomplete skeleton including femur (52 mm) and feathers (Zheng et al., 2014)
(STM 0-22) incomplete skeleton including gastralia (Zheng et al., 2014)
(STM 0-23) incomplete skeleton including gastralia and femur (75 mm) (Zheng et al., 2014)
(STM 0-24) material including gastralia and femur (50 mm) (Zheng et al., 2014)
(STM 0-25) material including gastralia and femur (62 mm) (Zheng et al., 2014)
(STM 0-26) incomplete skeleton including gastralia and femur (93 mm) (Zheng et al., 2014)
(STM 0-27) incomplete skeleton including gastralia, femur (52 mm) and feathers (Zheng et al., 2014)
(STM 0-28) incomplete skeleton including femur (75 mm) and feathers (Zheng et al., 2014)
(STM 0-29) incomplete skeleton including gastralia, femur ( mm) and feathers (Zheng et al., 2014)
(STM 0-30) incomplete skeleton including gastralia, femur (50 mm) and feathers (Zheng et al., 2014)
(STM 0-31) incomplete skeleton including gastralia,scapula, coracoid, furcula, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 0-32) incomplete skeleton including gastralia, femur (40 mm) and feathers (Zheng et al., 2014)
(STM 0-33) material including femur (50 mm) and feathers (Zheng et al., 2014)
(STM 0-34) incomplete skeleton including gastralia and femur (70 mm) (Zheng et al., 2014)
(STM 0-35) incomplete skeleton including gastralia, femur (80 mm) and feathers (Zheng et al., 2014)
(STM 0-36) incomplete skeleton including femur (71 mm) and feathers (Zheng et al., 2014)
(STM 0-37) incomplete skeleton including gastralia, femur (67 mm) and feathers (Zheng et al., 2014)
(STM 0-38) incomplete skeleton including femur (45 or 40.5 mm), feathers and gastric pellet (30 mm) (Zheng et al., 2014)
(STM 0-39) incomplete skeleton including gastralia, femur (40 mm) and feathers (Zheng et al., 2014)
(STM 0-40) incomplete skeleton including gastralia, femur (65 mm) and feathers (Zheng et al., 2014)
(STM 0-41) incomplete skeleton including gastralia, femur (50 mm) and feathers (Zheng et al., 2014)
(STM 0-42) incomplete skeleton including gastralia and femur (60 mm) (Zheng et al., 2014)
(STM 0-43) material including femur (72 mm) (Zheng et al., 2014)
(STM 0-44) incomplete skeleton including gastralia and femur (60 mm) (Zheng et al., 2014)
(STM 0-45) (Zheng et al., 2014)
(STM 0-46) material including gastralia and femur (60 mm) (Zheng et al., 2014)
(STM 0-47) incomplete skeleton including gastralia, femur (68 mm) and feathers (Zheng et al., 2014)
(STM 0-48) incomplete skeleton including gastralia, femur (71 mm) and feathers (Zheng et al., 2014)
(STM 0-49) material including gastralia and femur (67 mm) (Zheng et al., 2014)
(STM 0-50) incomplete skeleton including gastralia, femur (65 mm) and feathers (Zheng et al., 2014)
(STM 0-51) material including gastralia and femur (~50 mm) (Zheng et al., 2014)
(STM 0-52) incomplete skeleton including dorsal vertebrae, dorsal ribs, gastralia, coracoids, humerus, pubes, femur (57 mm) and feathers (Zheng et al., 2014)
(STM 0-53) incomplete skeleton including gastralia, femur (56 mm) and feathers (Zheng et al., 2014)
(STM 0-54) incomplete skeleton including femur (49.5 mm) and feathers (Zheng et al., 2014)
(STM 0-55) incomplete skeleton including gastralia, femur (60 mm) and feathers (Zheng et al., 2014)
(STM 0-56) incomplete skeleton including gastralia, femur (42 mm) and feathers (Zheng et al., 2014)
(STM 0-57) incomplete skeleton including femur (44 mm) and feathers (Zheng et al., 2014)
(STM 0-58) incomplete skeleton including femur (49 mm) and feathers (Zheng et al., 2014)
(STM 0-59) incomplete skeleton including gastralia, femur (47 mm) and feathers (Zheng et al., 2014)
(STM 0-60) material including dorsal vertebrae, dorsal ribs, gastralia, sacral vertebrae, ilium, pubes, ischia, femur (45 mm) and feathers (Zheng et al., 2014)
(STM 0-61) incomplete skeleton including femur (66 mm) (Zheng et al., 2014)
(STM 0-62) incomplete skeleton including femur (49 mm) and feathers (Zheng et al., 2014)
(STM 0-63) material including gastralia, femur (~60 mm) and feathers (Zheng et al., 2014)
(STM 0-64) incomplete skeleton including gastralia, femur (60 mm) and feathers (Zheng et al., 2014)
(STM 0-66) specimen including femur (60 mm) and feathers (Zheng et al., 2014)
(STM 0-67) material including gastralia, femur (~43 mm) and feathers (Zheng et al., 2014)
(STM 0-68) incomplete skeleton including gastralia and feathers (Zheng et al., 2014)
(STM 0-69) incomplete skeleton including gastralia, femur (60 mm) and feathers (Zheng et al., 2014)
(STM 0-70) material including femur (65 mm) and feathers (Zheng et al., 2014)
(STM 0-71) incomplete skeleton including gastralia, femur (64 mm) and feathers (Zheng et al., 2014)
(STM 0-72) incomplete skeleton including gastralia and femur (70 mm) (Zheng et al., 2014)
(STM 0-73) incomplete skeleton including gastralia and femur (62 mm) (Zheng et al., 2014)
(STM 0-74) incomplete skeleton including gastralia and femur (50 mm) (Zheng et al., 2014)
(STM 0-75) incomplete skeleton including gastralia and femur (50 mm) (Zheng et al., 2014)
(STM 0-76) incomplete skeleton including gastralia, femur (55 mm) and feathers (Zheng et al., 2014)
(STM 0-77) incomplete skeleton including gastralia and femur (49 mm) (Zheng et al., 2014)
(STM 0-78) incomplete skeleton including gastralia and femur (51 mm) (Zheng et al., 2014)
(STM 0-79) incomplete skeleton including gastralia, femur (49 mm) and feathers (Zheng et al., 2014)
(STM 0-80) incomplete skeleton including gastralia, femur (~38 mm) and feathers (Zheng et al., 2014)
(STM 0-81) material including gastralia and femur (~32 mm) (Zheng et al., 2014)
(STM 0-82) incomplete skeleton including gastralia, femur (47 mm) and feathers (Zheng et al., 2014)
(STM 0-83) material including gastralia and femur (~39 mm) (Zheng et al., 2014)
(STM 0-84) material including gastralia and femur (52 mm) (Zheng et al., 2014)
(STM 0-85) incomplete skeleton including gastralia and femur (44 mm) (Zheng et al., 2014)
(STM 0-86) incomplete skeleton including femur (60 mm) and feathers (Zheng et al., 2014)
(STM 0-87) material including gastralia, femur (62 mm) and feathers (Zheng et al., 2014)
(STM 0-88) material including gastralia, femur (~66 mm) (Zheng et al., 2014)
(STM 0-89) incomplete skeleton including gastralia, femur (60 mm) and feathers (Zheng et al., 2014)
(STM 0-90) material including gastralia, femur (79 mm) and feathers (Zheng et al., 2014)
(STM 0-91) material including gastralia and femur (70 mm) (Zheng et al., 2014)
(STM 0-92) incomplete skeleton including gastralia and femur (64 mm) (Zheng et al., 2014)
(STM 0-93) incomplete skeleton including skull, cervical vertebrae, dorsal vertebrae, dorsal ribs, gastralia, caudal vertebrae, scapula, coracoid, furcula, humeri, radii, ulnae, manus, ilium, pubes, femora (69 mm), tibiae, metatarsi and feathers (Zheng et al., 2014)
(STM 0-94) material including gastralia (Zheng et al., 2014)
(STM 0-95) material including gastralia and femur (60 mm) (Zheng et al., 2014)
(STM 0-96) incomplete skeleton including gastralia, femur (~48 mm) and feathers (Zheng et al., 2014)
(STM 0-97) incomplete skeleton including gastralia and femur (58 mm) (Zheng et al., 2014)
(STM 0-98) incomplete skeleton including feathers (Zheng et al., 2014)
(STM 0-99) incomplete skeleton including gastralia and femur (76 mm) (Zheng et al., 2014)
(STM 0-100) incomplete skeleton including femur (74 mm) (Zheng et al., 2014)
(STM 0-101) material including femur (60 mm) (Zheng et al., 2014)
(STM 0-102) incomplete skeleton including gastralia and femur (66 mm) (Zheng et al., 2014)
(STM 0-103) (Zheng et al., 2014)
(STM 0-104) incomplete skeleton including gastralia, femur (43 mm) and feathers (Zheng et al., 2014)
(STM 0-105) incomplete skeleton including gastralia, femur (72 mm) and feathers (Zheng et al., 2014)
(STM 0-106) incomplete skeleton including gastralia, femur (75 mm) and feathers (Zheng et al., 2014)
(STM 0-107) material including feathers (Zheng et al., 2014)
(STM 0-108) material including gastralia, femur (62 mm) and feathers (Zheng et al., 2014)
(STM 0-109) material including feathers (Zheng et al., 2014)
(STM 0-110) incomplete skeleton including gastralia, femur (57 mm) and feathers (Zheng et al., 2014)
(STM 0-111) incomplete skeleton including gastralia, femur (65 mm) and feathers (Zheng et al., 2014)
(STM 0-112) incomplete skeleton including gastralia, femur (~63 mm) and feathers (Zheng et al., 2014)
(STM 0-113) material including gastralia and femur (48 mm) (Zheng et al., 2014)
(STM 0-114) material including dorsal ribs, caudal series, humerus, radius, ulna, metacarpal II, metacarpal III, femur (50 mm), tibiae, metatarsal I, phalanx I-1, pedal ungual I, metatarsi, phalanx II-1, phalanx III-1, pes, scales, skin, propatagium and feathers (Zheng et al., 2014)
(STM 0-115) material including gastralia and feathers (Zheng et al., 2014)
(STM 0-116) material including femur (41 mm) (Zheng et al., 2014)
(STM 0-117) material including feathers (Zheng et al., 2014)
(STM 0-118) incomplete skeleton including premaxilla, mandible, gastralia, caudal vertebrae, humerus, radius, ulna, metacarpal II, metacarpal III, pubis, ischium, femora (62 mm), tibiae, fibula, metatarsal I, phalanx II-1, phalanx III-1, skin and feathers (Zheng et al., 2014)
(STM 0-119) incomplete skeleton including gastralia, femur (60 mm) and feathers (Zheng et al., 2014)
(STM 0-120) material including dorsal vertebrae, dorsal ribs, gastralia, humeri, femora (48 mm) and feathers (Zheng et al., 2014)
(STM 0-121) incomplete skeleton including gastralia and femur (44 mm) (Zheng et al., 2014)
(STM 0-122) material including gastralia and feathers (Zheng et al., 2014)
(STM 0-123) material including gastralia, femur (60 mm) and feathers (Zheng et al., 2014)
(STM 0-124) material including feathers (Zheng et al., 2014)
(STM 0-125) material including caudal vertebrae, humerus, radius, ulna, metacarpal II, metacarpal III, femur (59 mm), tibia, fibula, metatarsal I, metatarsals, scales and feathers (Zheng et al., 2014)
(STM 0-126) incomplete skeleton including gastralia, femur (54 mm) and feathers (Zheng et al., 2014)
(STM 0-127) material including humerus, radius, ulna, scapholunare, semilunate carpal, metacarpal I, metacarpal II, metacarpal III, ischium, femur (70 mm), tibia, fibula, metatarsal I, phalanx II-1, phalanx III-1 skin and propatagium (Zheng et al., 2014)
(STM 0-128) material including gastralia and femur (~50 mm) (Zheng et al., 2014)
(STM 0-129) material including gastralia, femur (~46 mm) and feathers (Zheng et al., 2014)
(STM 0-130) material including gastralia and femur (60 mm) (Zheng et al., 2014)
(STM 0-131) material including gastralia and feathers (Zheng et al., 2014)
(STM 0-132) incomplete skeleton including premaxilla, mandible, gastralia, caudal vertebrae, radius, ulna, metacarpal I, phalanx I-1, metacarpal II, metacarpal III, ischium, femur (40 mm), tibia, fibula, metatarsal I, phalanx II-1, phalanx III-1, skin and feathers (Zheng et al., 2014)
(STM 0-133) material including humerus, radius, ulna, metacarpal II, metacarpal III, tibia, metatarsals, skin and scales (Zheng et al., 2014)
(STM 0-134) incomplete skeleton including femur (40 mm) and feathers (Zheng et al., 2014)
(STM 0-135) incomplete skeleton including gastralia and femur (60 mm) (Zheng et al., 2014)
(STM 0-136) material including gastralia, femur (47 mm) and feathers (Zheng et al., 2014)
(STM 0-137) incomplete skeleton including gastralia, femur (72 mm) and feathers (Zheng et al., 2014)
(STM 0-138) incomplete skeleton including gastralia, femur (65 mm) and feathers (Zheng et al., 2014)
(STM 0-139) incomplete skeleton including feathers (Zheng et al., 2014)
(STM 0-140) incomplete skeleton including gastralia, femur (43 mm) and feathers (Zheng et al., 2014)
(STM 0-141) incomplete skeleton including gastralia, femur (50 mm) and feathers (Zheng et al., 2014)
(STM 0-142) incomplete skeleton including gastralia, femur (41 mm) and feathers (Zheng et al., 2014)
(STM 0-143) incomplete skeleton including gastralia, femur (68 mm) and feathers (Zheng et al., 2014)
(STM 0-144) incomplete skeleton including premaxilla, mandible, gastralia, caudal series, humerus, radius, ulna, carpals, metacarpal I, phalanx I-1, manual ungual I, metacarpal II, phalanx II-1, phalanx II-2, metacarpal III, phalanx III-1, phalanx III-2, phalanx III-3, manual claw sheath, femur (~50 mm), tibia, fibula, metatarsal I, phalanx II-1, phalanx III-1, skin, propatagium, body feathers and remiges (Zheng et al., 2014)
(STM 0-145) incomplete skeleton including gastralia and femur (50 mm) (Zheng et al., 2014)
(STM 0-146) material including gastralia (Zheng et al., 2014)
(STM 0-147) incomplete skeleton including premaxilla, mandible, gastralia, radius, ulna, metacarpal II, metacarpal III, femur (~35 mm), tibia, metatarsal I, metatarsus, phalanx II-1, phalanx III-1, pedal phalanges, pedal ungual IV and skin (Zheng et al., 2014)
(STM 0-148) incomplete skeleton including gastralia and femur (40 mm) (Zheng et al., 2014)
(STM 0-149) material including feathers (Zheng et al., 2014)
(STM 0-150) incomplete skeleton including gastralia, femur (50 mm) and feathers (Zheng et al., 2014)
(STM 0-151) incomplete skeleton including femur (69 mm) and feathers (Zheng et al., 2014)
(STM 0-152) incomplete skeleton including gastralia, femur (68 mm) and feathers (Zheng et al., 2014)
(STM 0-153) material including gastralia, femur (44 mm) and feathers (Zheng et al., 2014)
(STM 0-154) incomplete skeleton including gastralia, femur (50 mm) and feathers (Zheng et al., 2014)
(STM 0-155) incomplete skeleton including gastralia, femur (73 mm) and feathers (Zheng et al., 2014)
(STM 0-156) incomplete skeleton including gastralia and femur (50 mm) (Zheng et al., 2014)
(STM 0-157) incomplete skeleton including gastralia, femur (54 mm) and feathers (Zheng et al., 2014)
(STM 0-158) incomplete skeleton including gastralia, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 0-159) material including gastralia, femur (58 mm) and feathers (Zheng et al., 2014)
(STM 0-160) incomplete skeleton including gastralia (Zheng et al., 2014)
(STM 0-161) incomplete skeleton including gastralia and femur (75 mm) (Zheng et al., 2014)
(STM 0-162) incomplete skeleton including gastralia, femur (~53 mm) and feathers (Zheng et al., 2014)
(STM 0-163) material including femur (48 mm) and feathers (Zheng et al., 2014)
(STM 0-164) incomplete skeleton including gastralia, femur (47 mm) and feathers (Zheng et al., 2014)
(STM 0-165) incomplete skeleton including dorsal vertebrae, dorsal ribs, gastralia, sacrum, scapulae, coracoid, furcula, humeri, radius, ulna, manus, pubes, ischium, femora (63 mm) and feathers (Zheng et al., 2014)
(STM 0-166) incomplete skeleton including gastralia, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 0-167) incomplete skeleton including gastralia and femur (45 mm) (Zheng et al., 2014)
(STM 0-168) incomplete skeleton including gastralia and femur (56 mm) (Zheng et al., 2014)
(STM 0-169) incomplete skeleton including gastralia, femur (72 mm) and feathers (Zheng et al., 2014)
(STM 0-170) incomplete skeleton including gastralia, femur (64 mm) and feathers (Zheng et al., 2014)
(STM 0-171) incomplete skeleton including gastralia, femur (53 mm) and feathers (Zheng et al., 2014)
(STM 0-172) material including femur (70 mm) and feathers (Zheng et al., 2014)
(STM 0-173) incomplete skeleton including gastralia, femur (60 mm) and feathers (Zheng et al., 2014)
(STM 0-174) incomplete skeleton including gastralia and femur (50 mm) (Zheng et al., 2014)
(STM 0-175) incomplete skeleton including gastralia, femur (75 mm) and feathers (Zheng et al., 2014)
(STM 0-176) incomplete skeleton including gastralia and femur (68 mm) (Zheng et al., 2014)
(STM 0-177) incomplete skeleton including gastralia, femur (69 mm) and feathers (Zheng et al., 2014)
(STM 0-178) incomplete skeleton including gastralia, femur (63 mm) and feathers (Zheng et al., 2014)
(STM 0-179) incomplete skeleton including skull, mandibles, cervical vertebrae, cervical ribs, femur (65 or 71 mm), feathers and gastric pellet including at least three squamates (53 mm) (Zheng et al., 2014)
(STM 0-180) material including feathers (Zheng et al., 2014)
(STM 0-181) incomplete skeleton including gastralia, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 0-182) incomplete skeleton including gastralia, femur (43 mm) and feathers (Zheng et al., 2014)
(STM 0-183) incomplete skeleton including gastralia and femur (50 mm) (Zheng et al., 2014)
(STM 0-184) incomplete skeleton including gastralia (Zheng et al., 2014)
(STM 0-185) incomplete skeleton including femur (65 mm) (Zheng et al., 2014)
(STM 0-186) incomplete skeleton including gastralia, femur (46 mm) and feathers (Zheng et al., 2014)
(STM 0-187) incomplete skeleton including gastralia, femur (42 mm) and feathers (Zheng et al., 2014)
(STM 0-188) incomplete skeleton including gastralia, femur (75 mm) and feathers (Zheng et al., 2014)
(STM 0-189) incomplete skeleton including gastralia and femur (44 mm) (Zheng et al., 2014)
(STM 0-190) incomplete skeleton including gastralia and femur (54 mm) (Zheng et al., 2014)
(STM 0-191) incomplete skeleton including gastralia and femur (68 mm) (Zheng et al., 2014)
(STM 0-192) incomplete skeleton including gastralia and femur (75 mm) (Zheng et al., 2014)
(STM 0-193) incomplete skeleton including gastralia, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 0-194) incomplete skeleton including gastralia, femur (46 mm) and feathers (Zheng et al., 2014)
(STM 0-195) material including femur (43 mm) (Zheng et al., 2014)
(STM 0-196) material including gastralia and feathers (Zheng et al., 2014)
(STM 0-197) material including gastralia and feathers (Zheng et al., 2014)
(STM 0-198) incomplete skeleton including gastralia, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 0-199) material including gastralia and feathers (Zheng et al., 2014)
(STM 0-200) incomplete skeleton including gastralia (Zheng et al., 2014)
(STM 0-201) material including gastralia, femur (65 mm) and feathers (Zheng et al., 2014)
(STM 0-202) incomplete skeleton including gastralia, femur (60 mm) and feathers (Zheng et al., 2014)
(STM 0-203) incomplete skeleton including gastralia and femur (62 mm) (Zheng et al., 2014)
(STM 0-204) incomplete skeleton including gastralia, femur (64 mm) and feathers (Zheng et al., 2014)
(STM 0-205) material including femur (60 mm) (Zheng et al., 2014)
(STM 0-206) incomplete skeleton including gastralia, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 0-207) incomplete skeleton including gastralia, femur (51 mm) and feathers (Zheng et al., 2014)
(STM 0-208) incomplete skeleton including femur (70 mm) and feathers (Zheng et al., 2014)
(STM 0-209) incomplete skeleton including gastralia, femur (50 mm) and feathers (Zheng et al., 2014)
(STM 0-210) incomplete skeleton including gastralia and feathers (Zheng et al., 2014)
(STM 0-211) incomplete skeleton including femur (58 mm) and feathers (Zheng et al., 2014)
(STM 0-212) incomplete skeleton including gastralia, femur (45 mm) and feathers (Zheng et al., 2014)
(STM 0-213) incomplete skeleton including gastralia, femur (71 mm) and feathers (Zheng et al., 2014)
(STM 0-214) incomplete skeleton including gastralia and feathers (Zheng et al., 2014)
(STM 0-215) incomplete skeleton including femur (68 mm) and feathers (Zheng et al., 2014)
(STM 0-216) incomplete skeleton including femur (67 mm) and feathers (Zheng et al., 2014)
(STM 0-217) incomplete skeleton including gastralia, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 0-218) material including gastralia and femur (66 mm) (Zheng et al., 2014)
(STM 0-219) material including gastralia, femur (~46 mm) and feathers (Zheng et al., 2014)
(STM 0-220) material including gastralia, femur (~50 mm) and feathers (Zheng et al., 2014)
(STM 0-221) incomplete skeleton including femur (73 mm) and feathers (Zheng et al., 2014)
(STM 0-222) material including femur (50 mm) (Zheng et al., 2014)
(STM 0-223) material including gastralia, femur (46 mm) and feathers (Zheng et al., 2014)
(STM 0-224) skull, mandible, hyoid, cervical series, dorsal vertebrae, dorsal ribs, gastralia, first to ~fifteenth caudal vertebrae, furcula, humeri, radii, ulnae, metacarpals I, phalanges I-1, manual ungual I, metacarpals II, phalanx II-1, phalanx II-2, manual ungual II, metacarpals III, phalanax III-1, phalanx III-2, phalanx III-3, manual ungual III, ilium, femora (80 or 70 mm), tibiae, metatarsi, pedal phalanges and unguals, feathers and gastric pellet (39 mm) (Zheng et al., 2014)
(STM 0-225) incomplete skeleton including gastralia and femur (60 mm) (Zheng et al., 2014)
(STM 0-226) (Zheng et al., 2014)
(STM 0-227) gastric pellet including ptycholepid fish scales and bones (45 mm) (Zhang et al., 2018)
(STM 0-228) gastric pellet including ptycholepid fish scales and bones (35 mm) (Zhang et al., 2018)
(STM A0-4) skull, sclerotic plates, mandibles, cervical series, dorsal series, partial dorsal ribs, sacrum, first to ~eighteenth caudal vertebrae, scapulae, coracoids, humeri, radius, ulnae, metacarpals I, phalanges I-1, manual unguals I, metacarpals II, phalanges II-1, phalanges II-2, manual ungual II, metacarpals III, phalanx III-1, phalanges III-2, phalanges III-3, manual unguals III, manual claw sheaths, femora (~35 mm), tibia, metatarsi, pedal phalanges, pedal unguals, gastric pellet (17 mm) (Zheng et al., 2018)
(XHPM 1084) specimen including skull and manus (Foth and Rauhut, 2017)
(YFGP-T5199) (470 mm adult) skull (59.5 mm), mandibles, eight cervical vertebrae (series 56.5 mm), cervical ribs, seven dorsal vertebrae (series 97.5 mm), dorsal ribs, gastralia, caudal series (236.5 mm; proximal caudal 6.5, distal caudal 16 mm), chevron, scapulae (31 mm), coracoids, furcula, humeri (70 mm), radii, ulnae (59.5 mm), scapholunares, semilunate carpal, distal carpals III, metacarpals I (14 mm), phalanges I-1 (27 mm), manual unguals I (16.5 mm), metacarpals II (~38 mm), phalanges II-1 (25 mm), phalanges II-2, manual ungual II, metacarpals III (~31 mm), phalanx III-1, phalanx III-2, phalanx III-3, manual ungual III, ilia (35.5 mm), pubes (49.5 mm), ischium (16 mm), femora (69.5 mm), tibiotarsi (106 mm), metatarsals I (12 mm), phalanges I-1, pedal unguals I, metatarsals II, phalanges II-1, phalanges II-2, pedal unguals II, metatarsals III (61 mm), phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, metatarsals IV, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanx IV-4, pedal ungual IV, metatarsal V, body feathers, remiges, retrices (Lefèvre et al., 2014; described by Lindgren et al., 2015)
Other diagnoses- Xu et al. (2008) suggested a short ischium (less than one-fourth of the femoral length) as being diagnostic, but the holotype's ischium is only partially exposed and of published measured specimens only YFGP-T5199 has such a short ischium (23%). Other specimens (41HIII 0404 32%; 41HIII 0415 29%; BMNHC Ph 804 37%; BMNHC Ph 823 33%; LPM-B00169 34%) are longer than Eosinopteryx (28%) and Aurornis (27%). They also listed 'ventral surface of coracoid sculptured by numerous small pits' as diagnostic, but this seems present in Eosinopteryx as well (unexposed in Aurornis).
Hu et al. (2009) suggested an elongate tibiotarsus as diagnostic, but the tibiofemoral ratios in e.g. 41HIII 0404 and BMNHC Ph 823 are the same or less than Aurornis and/or Eosinopteryx.
Pei et al. (2017) listed several characters that were also stated to be present in other 'anchiornithines'- straight nasal process of premaxilla; short anterior ramus of maxilla; ventrally displaced promaxillary fenestra; sheet-like posteroventral process of dentary; deltopectoral crest no longer than one-fourth of humeral shaft; straight ulna; straight radius; fibula with extremely expanded proximal end as anteroposteriorly broad as tibia.
Comments- The holotype was discovered by a farmer (Hu et al., 2009) and given to the IVPP before October 2008. Foth and Rauhut (2017) include high resolution photos of the holotype manus.
Jiang (2011) describes complete skeleton C.0502 as a new species of Anchiornis in a thesis. Though described as having thirteen dorsals and four sacrals, the supposed last dorsal appears to be a first sacral. The ilium is reconstructed with a very short preacetabular process, but it is near certainly just broken.
While Xu et al. (2008) used a version of the Theropod Working Group matrix with added characters from Xu's thesis to place Anchiornis as an avialan more basal than Archaeopteryx, Hu et al. (2009) used Senter's version of the TWiG matrix to place it as a troodontid more derived than Sinovenator but less so than Mei and other taxa. Xu et al. (2011) found it to be an archaeopterygid, with that group basal in Deinonychosauria. Hartman et al. (2019) found Anchiornis to be an archaeopterygid, which resolved as basal deinonychosaurs, or with one extra step sister to troodontids or basal avialans. Its monophyly relative to Aurornis and Eosinopteryx has not been established.
References- Xu, Zhao, Norell, Sullivan, Hone, Erickson, Wang, Han and Guo, 2008. A new feathered maniraptoran dinosaur fossil that fills a morphological gap in avian origin. Chinese Science Bulletin. 54(3), 430-435.
Hu, Hou, Zhang and Xu, 2009. A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus. Nature. 461, 640-643.
Li, Gao, Vinther, Shawkey, Clarke, D'Alba, Meng, Briggs and Prum, 2010. Plumage color patterns of an extinct dinosaur. Science. 327 (5971), 1369-1372.
Jiang, 2011. A new discovery of Anchiornis from western of Liaoning, China. Masters thesis, Chengdu University of Technology. 101 pp.
Xu, You, Du and Han, 2011. An Archaeopteryx-like theropod from China and the origin of Avialae. Nature. 475, 465-470.
Longrich, Vinther, Meng, Li and Russell, 2012. Primitive wing feather arrangement in Archaeopteryx lithographica and Anchiornis huxleyi. Current Biology. 22(23), 2262-2267.
Pei, Li, Meng, Norell and Gao, 2013. Excellently preserved new specimens of Anchiornis and the implication of early evolution in Paraves. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 189.
Foth, 2014. Comment on the absence of ossified sternal elements in basal paravian dinosaurs. Proceedings of the National Academy of Sciences. 111(50), E5334.
Lefèvre, Cau, Hu, Wu, Escuillié and Godefroit, 2014. New basal Avialae from the Jurassic of China. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 167.
O'Connor, Wang, Zheng and Zhou, 2014. Reply to Foth: Preserved cartilage is rare but not absent: Troodontid sternal plates are absent, not rare. Proceedings of the National Academy of Sciences. 111(50), E5335.
Zheng, O'Connor, Wang, Wang, Zhang and Zhou, 2014. On the absence of sternal elements in Anchiornis (Paraves) and Sapeornis (Aves) and the complex early evolution of the avian sternum. Proceedings of the National Academy of Sciences. 111(38), 13900-13905.
Lindgren, Sjövall, Carney, Cincotta, Uvdal, Hutcheson, Gustafsson, Lefèvre, Escuillié, Heimdal, Engdahl, Gren, Kear, Wakamatsu, Yans and Godefroit, 2015. Molecular composition and ultrastructure of Jurassic paravian feathers. Scientific Reports. 5, 13520.
Pei, 2015. New paravian fossils from the Mesozoic of east Asia and their bearing on the phylogeny of the Coelurosauria. PhD thesis, Columbia University. 545 pp.
Foth and Rauhut, 2017. Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs. BMC Evolutionary Biology. 17:236.
Lefèvre, Cau, Cincotta, Hu, Chinsamy, Escuillié and Godefroit, 2017. A new Jurassic theropod from China documents a transitional step in the macrostructure of feathers. The Science of Nature. 104:74.
Pei, Li, Meng, Norell and Gao, 2017. New specimens of Anchiornis huxleyi (Theropoda: Paraves) from the Late Jurassic of northeastern China. Bulletin of the American Museum of Natural History. 411, 66 pp.
Wang, Pittman, Zheng, Kaye, Falk, Hartman and Xu, 2017. Basal paravian functional anatomy illuminated by high-detail body outline. Nature Communications. 8:14576.
Guo, Xu and Jia, 2018. Morphological and phylogenetic study based on new materials of Anchiornis huxleyi (Dinosauria, Theropoda) from Jianchang, western Liaoning, China. Acta Geologica Sinica. 92(1), 1-15.
Rauhut, Foth and Tischlinger, 2018. The oldest Archaeopteryx (Theropoda: Avialiae): A new specimen from the Kimmeridgian/Tithonian boundary of Schamhaupten, Bavaria. PeerJ. 6:e4191.
Zheng, Wang, Sullivan, Zhang, Zhang, Wang, Li and Xu, 2018. Exceptional dinosaur fossils reveal early origin of avian-style digestion. Scientific Reports. 8:14217.

Aurornis Godefroit, Cau, Hu, Escuillié, Wu and Dyke, 2013
A. xui Godefroit, Cau, Hu, Escuillié, Wu and Dyke, 2013
Oxfordian, Late Jurassic
Yaolugou, Tiaojishan Formation, Liaoning, China
Holotype- (YFGP-T5198) (510 mm adult) skull (57 mm), mandibles, seven cervical vertebrae (series 62 mm), cervical ribs, eleven dorsal vertebrae (series 97 mm), dorsal ribs, synsacrum (30 mm), about thirty caudal vertebrae (series 265 mm), chevrons, scapulae (36.6 mm), coracoid, furcula, humeri (58 mm), radii, ulnae (57 mm), scapholunare, pisiform, semilunate carpal, metacarpal I (12 mm), phalanx I-1 (27 mm), manual ungual I, metacarpals II (34 mm), phalanx II-1 (14.5 mm), incomplete phalanx II-2, metacarpals III (34.5 mm), phalanx III-1, phalanx III-2, phalanx III-3, incomplete manual ungual III, ilia (34.8 mm), pubes (55 mm), ischia (~18 mm), femora (66 mm), tibiotarsi (90.5 mm), partial metatarsal I, phalanx I-1, pedal ungual I, metatarsi (44 mm), phalanges II-1 (7 mm), phalanx II-2 (9 mm), pedal ungual II, phalanges III-1 (12 mm), phalanx III-2 (6.5 mm), phalanx III-3 (6 mm), pedal ungual III (7.5 mm), phalanges IV-1, phalanx IV-2, phalanx IV-3 (5 mm), phalanx IV-4 (5 mm), pedal ungual IV (7 mm), body feathers
Diagnosis- (modified after Godefroit et al., 2013) manual phalanx I-1 distinctly more robust than radius; robust postacetabular process of ilium not markedly deflected ventrally and with horizontal dorsal margin; distal end of ischium dorsoventrally expanded and formed by hook-like ventral process delimiting a prominent distal obturator notch and by a longer dorsal distal process.
Other diagnoses- Godefroit et al. also list "metatarsal I gracile and elongate (about 30% of metatarsal III length)", but this is erroneous (see below).
Pei et al. (2017) claimed "The posterior (= postacetabular) process of the right ilium of YFGP-T5198 is more squared than in other Anchiornis, but the left posterior (= postacetabular) process of YFGP-T5198 is dorsoventrally shallow and has a posteroventrally sloping dorsal edge as in other Anchiornis specimens (e.g., IVPP V14378, LPMB00169, BMNHC Ph 804, BMNHC Ph 822, and BMNHC Ph 823)", but the left ilium seems to be in dorsal view.
Comments- The identification of some elements by Godefroit et al. (2013) is questionable. Instead of the surangular and angular being equal in depth as reconstructed, there is a suture showing the angular was much shallower as is usual for maniraptorans. The third manual digit is reconstructed as having two elongate proximal phalanges and a partially preserved third phalanx that would almost certainly make it longer than digit II. While the poor preservation and photo quality make any identification uncertain, there is a lateral bend halfway through and a short medial concavity that would support their phalanx III-1 being both III-1 and III-2. Thus their III-2 would be III-3, and their III-3 fragment would be most of ungual III, resembling the proportions of other basal paravians. Finally, metatarsal I is shown as being a third as long as III and untapered proximally, unlike any theropod. This apparent structure is formed by parts of the main metatarsal shafts before their surface is broken away more proximally. There does seem to be a small fragment of metatarsal I conntected to phalanx I-1.
The holotype is one of several paravian specimens acquired by the YFGP from a fossil dealer prior to June 2012. Pei et al. (2017) considered this probably a junior synonym of Anchiornis huxleyi.
The authors resolved Aurornis as a basal avialan using a reduced version of Cau's matrix, similar to Lee et al.'s (2014) later iteration of this matrix. Brusatte et al. (2014) found it to be a basal troodontid, however. All of these trees had the genus closely related to Eosinopteryx and Anchiornis, which are tentatively placed as archaeopterygids here.
References- Godefroit, Cau, Hu, Escuillié, Wu and Dyke, 2013. A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds. Nature. 498, 359-362.
Brusatte, Lloyd, Wang and Norell, 2014. Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition. Current Biology. 24(20), 2386-2392.
Lee, Cau, Naish and Dyke, 2014. Sustained miniaturization and anatomical innovation in the dinosaurian ancestors of birds. Science. 345(6196), 562-566.
Pei, Li, Meng, Norell and Gao, 2017. New specimens of Anchiornis huxleyi (Theropoda: Paraves) from the Late Jurassic of northeastern China. Bulletin of the American Muiseum of Natural History. 411, 66 pp.

unnamed archaeopterygid (Lefèvre, Cau, Hu, Wu, Escuillié and Godefroit, 2014)
Oxfordian, Late Jurassic
Tiaojishan Formation, Liaoning, China
Material- (YFGP-T5200) (juvenile) skull, mandible, hyoids, cervical series, dorsal vertebrae, dorsal ribs, gastralia, uncinate processes, sacrum, first to ~nineteenth caudal vertebrae, scapulae, coracoids, furcula, humeri, radii, ulnae, metacarpal I, phalanges I-1, manual unguals I, metacarpals II, phalanges II-1, phalanges II-2, manual unguals II, metacarpals III, phalanges III-1, phalanges III-2, phalanges III-3, manual unguals III, posterior ilia, pubes, femora (~46 mm), tibiae, fibulae, proximal tarsals, metatarsals I, phalanges I-1, pedal unguals I, metatarsals II, phalanx II-1, phalanx II-2, pedal ungual II, metatarsals III, phalanges III-1, phalanx III-2, phalanges III-3 (one distal), pedal unguals III, metatarsals IV, phalanges IV-1, phalanges IV-2, phalanx IV-3, phalanx IV-4, pedal unguals IV, body feathers, remiges, retrices, metatarsal remiges
Comments- Brougham (2013) added "three new undescribed Tiaojishan theropods" to three coelurosaur matrices, which his publically available poster (Brougham, online 2013) shows are labeled as YFGP-T5199, YFGP-T5200 and YFGP-T5201. However, YFGP-T5199 has since been described as an Anchiornis specimen (Lindgren et al., 2015; also figured in Lefèvre et al., 2017) which is not the same as Brougham figured. Lefèvre et al. (2014) also lists these three specimen numbers, but states "rectrices are well developed along the tail of YFGP-T5200", while Lefèvre et al.'s (2015) description of YFGP-T5200 corresponds to "YFGP-T5199" in Brougham's poster. Thus Brougham's numbers are incorrectly associated with specimens. Regardless, Brougham recovered all of these specimens in a clade with Aurornis and Eosinopteryx, Lefèvre et al. (2014) stated they were "basalmost Avialae" which is where Cau's matrix recovered Anchiornis-grade taxa at the time, and Lefèvre et al. (2015) found YFGP-T5200 to be "a basalmost Avialae forming a basal clade with Aurornis." They are thus here assigned to Archaeopterygidae, where the Hartman et al. matrix recovered Aurornis and Eosinopteryx.
As described by Lefèvre et al. (2015), YFGP-T5200 has symmetrical remiges, metatarsal remiges and retrices, with no barbules and the retrices extend down most of the tail as in Archaeopteryx.
References- Brougham, 2013. Multi-matrix analysis of new Late Jurassic feathered theropods from China supports troodontid-avialan clade. Symposium on Vertebrate Palaeontology and Comparative Anatomy, Programme and Abstracts. 49.
Brougham, 2013 online. https://www.researchgate.net/publication/280728942_SVPCA_Poster
Lefèvre, Cau, Hu, Wu, Escuillié and Godefroit, 2014. New basal Avialae from the Jurassic of China. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 167.
Lefèvre, Cau, Hu, Wu, Escuillié and Godefroit, 2015. A Jurassic avialan from China challenges the flight abilities in the earliest birds. Abstracts of the 12th Symposium on Mesozoic Terrestrial
Ecosystems. [pp]
Lindgren, Sjövall, Carney, Cincotta, Uvdal, Hutcheson, Gustafsson, Lefèvre, Escuillié, Heimdal, Engdahl, Gren, Kear, Wakamatsu, Yans and Godefroit, 2015. Molecular composition and ultrastructure of Jurassic paravian feathers. Scientific Reports. 5, 13520.
Lefèvre, Cau, Cincotta, Hu, Chinsamy, Escuillié and Godefroit, 2017. A new Jurassic theropod from China documents a transitional step in the macrostructure of feathers. Science of Nature. 104(9-10):74.

unnamed archaeopterygid (Lefèvre, Cau, Hu, Wu, Escuillié and Godefroit, 2014)
Oxfordian, Late Jurassic
Tiaojishan Formation, Liaoning, China
Material- (YFGP-T5201) skull, mandibles, hyoid, cervical series, dorsal series, dorsal ribs, gastralia, uncinate processes, synsacrum, caudal series, chevrons, scapulae, coracoids, furcula, humeri, radii (one proximal), ulnae, semilunate carpal, metacarpals I, phalanges I-1, manual unguals I, metacarpals II, phalanges II-1, phalanges II-2, manual ungual II, metacarpals III, phalanges III-1, phalanges III-2, phalanges III-3, manual unguals III, fragmentary ilia, pubes, ischia, femora (~69 mm), tibiae, fibulae, proximal tarsals, metatarsals I, phalanges I-1, pedal ungual I, metatarsals II, phalanges II-1, phalanges II-2, pedal unguals II, metatarsals III, phalanges III-1, phalanges III-2, proximal phalanges III-3, metatarsals IV, phalanges IV-1, phalanges IV-2, phalanx IV-3, phalanges IV-4 (one proximal), pedal ungual IV
Comments- Brougham (2013) added "three new undescribed Tiaojishan theropods" to three coelurosaur matrices, which his publically available poster (Brougham, online 2013) shows are labeled as YFGP-T5199, YFGP-T5200 and YFGP-T5201. As discussed in the YFGP-T5200 comments, Brougham's YFGP-T199 is actually YFGP-T5200, and the actual YFGP-T5199 Anchiornis specimen is not pictured. The other pictured specimens besides Aurornis (YFGP-T5198) and Eosinopteryx (YFGP-T5197) are the then-undescribed Serikornis (PMOL-AB00200; labeled YFGP-T5201) and an otherwise unpublished specimen (labeled YFGP-T5200). Thus unless Serikornis originally had a YFGP number, YFGP-5201 is assumed to be the skeleton in side view with no obvious remiges or retrices and an elongated upcurved snout. Brougham recovered all of these specimens in a clade with Aurornis and Eosinopteryx and Lefèvre et al. (2014) stated they were "basalmost Avialae" which is where Cau's matrix recovered Anchiornis-grade taxa at the time. They are thus here assigned to Archaeopterygidae, where the Hartman et al. matrix recovered Aurornis and Eosinopteryx.
Lefèvre et al. (2014) state "The skull of YFGP-T5201 displays several characters previously thought to be synapomorphic for Troodontidae."
References- Brougham, 2013. Multi-matrix analysis of new Late Jurassic feathered theropods from China supports troodontid-avialan clade. Symposium on Vertebrate Palaeontology and Comparative Anatomy, Programme and Abstracts. 49.
Brougham, 2013 online. https://www.researchgate.net/publication/280728942_SVPCA_Poster
Lefèvre, Cau, Hu, Wu, Escuillié and Godefroit, 2014. New basal Avialae from the Jurassic of China. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 167.

Eosinopteryx Godefroit, Demuynck, Dyke, Hu, Escuillié and Claeys, 2013
E. brevipenna Godefroit, Demuynck, Dyke, Hu, Escuillié and Claeys, 2013
Oxfordian, Late Jurassic
Yaolugou, Tiaojishan Formation, Liaoning, China
Holotype- (YFGP-T5197) (subadult) skull (43.2 mm), mandibles (40.2 mm), seven cervical vertebrae (series 39.6 mm), cervical ribs, dorsal vertebrae (series, 57.9 mm), dorsal ribs, gastralia, partial synsacrum (25.1 mm), caudal vertebrae 1-3 (~5.1 mm), fourth caudal vertebra (5.7 mm), fifth caudal vertebra (5.6 mm), sixth caudal vertebra (5.8 mm), seventh caudal vertebra (6.4 mm), eighth caudal vertebra (6.4 mm), ninth caudal vertebra (6.4 mm), tenth caudal vertebra (7.6 mm), eleventh caudal vertebra (9.6 mm), twelfth caudal vertebra (9.6 mm), thirteenth caudal vertebra (8.8 mm), fourteenth caudal vertebra (8 mm), fifteenth caudal vertebra (7.6 mm), sixteenth caudal vertebra (8 mm), seventeenth caudal vertebra (8 mm), eighteenth caudal vertebra (7.4 mm), nineteenth caudal vertebra (6.3 mm), twentieth caudal vertebra (9.2 mm), chevrons, scapulae (23.8 mm), coracoids, partial furcula, humeri (37.9 mm), radii (39.5 mm), ulnae (42 mm), scapholunare, semilunate carpal, metacarpals I, phalanges I-1 (one incomplete), manual unguals I (one partial), metacarpals II, phalanges II-1, phalanges II-2, manual unguals II, metacarpals III, phalanges III-1, phalanges III-2, phalanges III-3, manual ungual III, ilia (25 mm), incomplete pubis (35 mm), ischia (13.4 mm), femora (48.5 mm), tibiae (69.5 mm), metatarsal I, phalanx I-1, metatarsals II, phalanges II-1, phalanges II-2, pedal unguals II, metatarsals III (35.5 mm), phalanges III-1 (8.8 mm), phalanges III-2 (7.1 mm), phalanx III-3 (6.5 mm), pedal ungual III (6 mm), metatarsals IV, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanx IV-4, pedal ungual IV, body feathers, remiges
Diagnosis- (after Godefroit et al., 2013) short tail, composed of 20 caudal vertebrae, 2.7 times length of the femur.
Other diagnoses- Contra Godefroit et al.'s (2013) character "short snout, about 82% the length of the orbit", Pei et al. (2017) noted the snout "is broken and incomplete, and thus cannot be used for comparison" and that "the anteroposterior length of the preorbital portion of the skull is about 1.5-2 times that of the orbit, which is the same as in Anchiornis." Contra Godefroit et al.'s character "lacrimal with long posterior process participating in about half the length of dorsal margin of orbit and a vestigial anterior process", Pei et al. say "The lacrimal of [Anchiornis specimen] BMNHC Ph 804 has both long anterior and posterior processes, but both processes are extremely slender and easy to break, so the longer posterior process of the lacrimal is not a reliable diagnostic feature of Eosinopteryx." Contra Godefroit et al.'s character "chevrons reduced to small rod-like elements below the 8th or 9th caudal", Pei et al. state "Reduced chevrons below the proximal 8th or 9th caudal vertebrae are observed in other Anchiornis specimens, such as BMNHC Ph 804 and BMNHC Ph 822." Contra Godefroit et al.'s character "ilium with proportionally long, low and distally tapering postacetabular process (ratio 'length/height at midlength' = 5)", Pei et al. state "a long and low posterior (= postacetabular) process of the ilium is also present in Anchiornis (e.g., IVPP V14378, BMNHC Ph 804, BMNHC Ph 822, and BMNHC Ph 823)." Contra Godefroit et al.'s character "pedal unguals shorter than corresponding penultimate phalanges", Pei et al. suggest "Anchiornis specimens have variation in proportions of pedal phalanges, even within the same specimen, such as in BMNHC Ph 804." Finally, contra Godefroit et al.'s character "absence of rectrices (versus other paravians with preserved plumage) and feathers on metatarsus and pes (versus other troodontids with preserved plumage on the hindlimb)", Pei et al. state "The absence of rectrices and feathers on the metatarsus is possibly a preservational artifact, as many Anchiornis specimens only have feathers associated with few bones instead of the entire body."
Comments- The holotype is one of several paravian specimens acquired by the YFGP from a fossil dealer prior to June 2012. Plumage differences from e.g. Anchiornis are here seen as questionable, as other specimens which should originally possess pennaceous feathers on wings/tail also lack them, presumably due to preservation (Longipteryx holotype, NGMC 91, Epidexipteryx). Godefroit et al. (2013) claimed neurocentral and tibiotarsal fusion indicated a subdult or adult age, but Lefèvre et al. (2014) found histology showed it was immature.
The authors resolved Eosinopteryx as a basal troodontid using a version of Senter's TWiG matrix. Brusatte et al. (2014) also found Eosinpteryx to be a basal troodontid, while Foth et al. (2014) and Lee et al. (2014) both recovered it as a basal avialan closer to birds than troodontids. All of these trees had the genus closely related to Aurornis and Anchiornis, which are tentatively placed as archaeopterygids here.
References- Godefroit, Demuynck, Dyke, Hu, Escuillié and Claeys, 2013. Reduced plumage and flight ability of a new Jurassic paravian theropod from China. Nature. 498, 359-362.
Brusatte, Lloyd, Wang and Norell, 2014. Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition. Current Biology. 24(20), 2386-2392.
Foth, Tischlinger and Rauhut, 2014. New specimen of Archaeopteryx provides insights into the evolution of pennaceous feathers. Nature. 511, 79-82.
Lee, Cau, Naish and Dyke, 2014. Sustained miniaturization and anatomical innovation in the dinosaurian ancestors of birds. Science. 345(6196), 562-566.
Lefèvre, Cau, Hu, Wu, Escuillié and Godefroit, 2014. New basal Avialae from the Jurassic of China. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 167.
Pei, Li, Meng, Norell and Gao, 2017. New specimens of Anchiornis huxleyi (Theropoda: Paraves) from the Late Jurassic of northeastern China. Bulletin of the American Muiseum of Natural History. 411, 66 pp.

unnamed archaeopterygid (Louchart and Pouech, 2017)
Early-Middle Berriasian, Early Cretaceous
Cherves-de-Cognac, France
Material- (CHVm03.514) tooth (1.25x.98x.43 mm)
Comments- Louchart and Pouech (2017) described this as an archaeopterygid, but Rauhut et al. (2018) believed it "differs from the typical teeth of Archaeopteryx in the more compressed and less bulbous shape" and so referred it to Avialae indet.. However, the compression (BW/FABL 43%) is similar to e.g. the sixth maxillary tooth of the Daiting specimen (46%), so Louchert and Pouech's identification is accepted here.
References- Louchart and Pouech, 2017. A tooth of Archaeopterygidae (Aves) from the Lower Cretaceous of France extends the spatial and temporal occurrence of the earliest birds. Cretaceous Research. 73, 40-46.
Rauhut, Foth and Tischlinger, 2018. The oldest Archaeopteryx (Theropoda: Avialiae): A new specimen from the Kimmeridgian/Tithonian boundary of Schamhaupten, Bavaria. PeerJ. 6:e4191.

Archaeopteryx Meyer, 1861b
= Griphosaurus Wagner, 1862 (nomen rejectum)
= Griphornis Owen vide Woodward, 1862 (nomen rejectum)
= Archaeornis Petronievics vide Petroneivics and Woodward, 1917
= Jurapteryx Howgate, 1985
= Wellnhoferia Elzanowski, 2001
Other definitions- (Archaeopteryx lithographica <- Passer domesticus) (modified from Sereno, 1998)
A. lithographica Meyer, 1861b
= Griphornis longicaudatus Owen vide Woodward, 1862 (nomen rejectum)
= Griphosaurus problematicus Wagner vide Woodward, 1862 (nomen rejectum)
= Archaeopteryx macrura Owen, 1863 (nomen rejectum)
= Archaeopteryx siemensii Dames, 1897
= Archaeornis siemensii (Dames, 1897) Petronievics vide Petroneivics and Woodward, 1917
= Archaeopteryx oweni Petronievics, 1921
= Griphosaurus longicaudatus (Owen vide Woodward, 1862) Owen vide Brodkorb, 1963
= Archaeopteryx recurva Howgate, 1984
= Jurapteryx recurva (Howgate, 1984) Howgate, 1985
= Archaeopteryx bavarica Wellnhofer, 1993
= Wellnhoferia grandis Elzanowski, 2001
= Archaeopteryx albersdoerferi Kundrát, Nudds, Kear, Lü and Ahlberg, 2019
Early Tithonian, Late Jurassic
Upper Solnhofen Member of the Altmuhltal Formation, Germany
Neotype- (NHMUK 37001; London specimen; holotype of Griphosaurus; holotype of Griphosaurus problematicus; holotype of Griphornis longicaudatus; holotype of Archaeopteryx macrura; holotype of Archaeopteryx oweni) (.46 m, 450 g, 460 day old subadult) premaxilla, maxillary fragment, nasals, partial quadrate, braincase, cranial fragments, cervical centrum (7 mm), cervical neural arch, ninth cervical vertebra, tenth cervical vertebra, first dorsal vertebra (~7 mm), second dorsal vertebra, third dorsal vertebra, fourth dorsal vertebra, fifth dorsal vertebra, sixth dorsal vertebra (~7 mm), seventh dorsal vertebra (~7 mm), eighth dorsal vertebra, ninth dorsal vertebra, tenth dorsal vertebra, eleventh dorsal vertebra (5.5 mm), twelfth dorsal vertebra (5.5 mm), thirteenth dorsal vertebra (5.5 mm), dorsal ribs, gastralia, synsacrum (~33 mm) fourth caudal vertebra, fifth caudal vertebra, sixth caudal vertebra (6 mm), seventh caudal vertebra (6.5 mm), eighth caudal vertebra (8 mm), ninth caudal vertebra (~10.5 mm), tenth caudal vertebra (~10.5 mm), eleventh caudal vertebra (11.7 mm), twelfth caudal vertebra (12.3 mm), thirteenth caudal vertebra (13 mm), fourteenth caudal vertebra (12.3 mm), fifteenth caudal vertebra (12.5 mm), sixteenth caudal vertebra (12.4 mm), seventeenth caudal vertebra (11.4 mm), eighteenth caudal vertebra (11.4 mm), nineteenth caudal vertebra (10.5 mm), twentieth caudal vertebra (9.3 mm), twenty-first caudal vertebra (8.5 mm), twenty-second caudal vertebra (7 mm), twenty-third caudal vertebra (4.3 mm), scapulae (46 mm), coracoids, furcula, humeri (75 mm), radii (65 mm), ulnae (67.5 mm), scapholunare, pisiform, semilunate carpals, distal carpal III, partial metacarpal I, phalanx I-1, partial manual ungual I, metacarpals II (34.4 mm), phalanx II-2, manual ungual II, metacarpals III (one proximal), ilia (38 mm), pubes (51.5 mm), ischium (~25.5 mm), femora (60.5 mm), tibiae (80.5 mm), fibulae, astragalus, metatarsal I fragment, phalanx I-1 (8.8 mm), pedal ungual I (~6.8 mm), metatarsal II (~40 mm), phalanx II-1 (11 mm), phalanx II-2 (11 mm), pedal ungual II (~11 mm), metatarsal III (44 mm), phalanx III-1 (12.7 mm), phalanx III-2 (11 mm), phalanx III-3 (~9.5 mm), pedal ungual III (~14 mm), phalanx IV-4 , pedal ungual IV (~11 mm), remiges (130 mm), retrices (60-120 mm) (Meyer, 1861b)
Referred- ?(BMMS coll.; Ottmann and Steil specimen; chicken wing; ninth specimen) (420 day old juvenile) humerus (70.1 mm), radius (~59 mm), ulna (62 mm), semilunate carpal, metacarpal I (10 mm), phalanx I-1 (22.5 mm), metacarpal II (31.3 mm), phalanx II-1 (~16.5 mm), phalanx II-2 (21 mm), manual ungual II (~15 mm), metacarpal III (27.5 mm), phalanx III-1 (6.3 mm), phalanx III-2 (5 mm), phalanx III-3 (14.4 mm), manual ungual III (~10 mm), remiges (Wellnhofer and Roper, 2005)
?(BSP 1869 VIII 1; MB.Av.100; = HMN.Ab.100; holotype of Archaeopteryx lithographica) upper major primary covert feather (70.3 mm) (Meyer, 1861a)
(BSP 1999 I 50; Munich specimen; Solnhofen-Aktien-Verein specimen; seventh specimen; holotype of Archaeopteryx bavarica) (270 day old juvenile) partial skull (~45 mm), mandibles (40 mm), atlas, axis, third cervical vertebra, fourth cervical vertebra, fifth cervical vertebra, sixth cervical vertebra, seventh cervical vertebra, eighth cervical vertebra, ninth cervical neural spine, tenth cervical neural spine, cervical ribs, first dorsal neural spine, partial second dorsal vertebra, third dorsal neural spine, seventh dorsal neural spine, eighth dorsal vertebra, ninth dorsal vertebra, tenth dorsal vertebra, eleventh dorsal vertebra, twelfth dorsal vertebra, thirteenth dorsal vertebra, dorsal ribs, gastralia, (sacrum 22 mm) first sacral centrum, second sacral centrum, fifth sacral centrum, first caudal vertebra, second caudal vertebra, third caudal vertebra, fourth caudal vertebra, fifth caudal vertebra, sixth caudal vertebra, seventh caudal vertebra, eighth caudal vertebra, ninth caudal vertebra, tenth caudal vertebra, eleventh caudal vertebra, twelfth caudal vertebra, thirteenth caudal vertebra, fourteenth caudal vertebra, fifteenth caudal vertebra, sixteenth caudal vertebra, seventeenth caudal vertebra, eighteenth caudal vertebra, nineteenth caudal vertebra, twentieth caudal vertebra, twenty-first caudal vertebra, chevrons, scapulae (34.5 mm), coracoids (15 mm), partial furcula, humeri (~55 mm), radii (53 mm), ulnae (53 mm), pisiform, semilunate carpal, distal carpal III, metacarpal I (7 mm), phalanges I-1 (20 mm), manual unguals I (9.5 mm), metacarpals II (one distal; 25 mm), phalanges II-1 (12.5 mm), phalanges II-2 (18.5 mm), manual unguals II (10 mm), metacarpals III (one distal; ~23 mm), phalanges III-1 (one partial; 4.9 mm), phalanx III-2 (4.2 mm), phalanges III-3 (12 mm), manual unguals III (6.5 mm), manual claw sheaths, ilium (~27.5 mm), pubis (40 mm), ischia (~16 mm), incomplete femora (~46.5 mm), tibiae (~71.5 mm), fibula (69.5 mm), astragali, calcanea, two distal tarsals, metatarsals I, phalanges I-1 (7.1 mm), pedal ungual I (5.2 mm), metatarsals II (~36 mm), phalanges II-1 (~8 mm), phalanges II-2 (~8 mm), pedal unguals II (7, 7.4 mm), metatarsals III (40.5 mm), phalanges III-1 (10.8 mm), phalanges III-2 (8.5 mm), phalanges III-3 (8.4 mm), pedal unguals III (6.8, 7 mm), metatarsal IV (37 mm), phalanx IV-1 (8 mm), phalanx IV-2 (6 mm), phalanges IV-3 (~5.5 mm), phalanges IV-4 (7 mm), pedal unguals IV (6.2 mm), metatarsal V (~10 mm), pedal claw sheaths, remiges, retrices (Wellnhofer, 1993)
?(Opitsch coll.; Maxberg specimen; third specimen; lost) fourth cervical centrum, fifth cervical centrum, sixth cervical centrum, seventh cervical centrum, eighth cervical centrum, ninth cervical centrum, tenth cervical centrum, first dorsal centrum, second dorsal centrum, third dorsal centrum, fourth dorsal centrum, fifth dorsal centrum, sixth dorsal centrum, seventh dorsal centrum, eighth dorsal centrum, ninth dorsal centrum, tenth dorsal centrum, eleventh dorsal centrum, twelfth dorsal centrum, thirteenth dorsal vertebra, dorsal rib fragments, gastralia, first sacral vertebra, second sacral vertebra, third sacral vertebra, fourth sacral vertebra, fifth sacral vertebra, first caudal centrum, second caudal centrum, third caudal centrum, partial scapulae, coracoid, incomplete furcula, humeri (one incomplete; 72 mm), radii (63 mm), ulnae (one incomplete; ~62 mm), metacarpals I (~10 mm), distal phalanx I-1, manual unguals I (~12 mm), metacarpals II (~33 mm), phalanges II-1 (19 mm), phalanges II-2 (~22 mm), manual unguals II (~15 mm), metacarpals III (one proximal; 30 mm), phalanges III-1, phalanges III-2, phalanx III-3 (~16 mm), manual unguals III, manual claw sheath, partial ilium, pubes, ischium, femur (~58 mm), tibiae (one partial; ~79.5 mm), incomplete fibula, distal tarsal III, distal tarsal IV, metatarsal I, phalanx I-1, pedal ungual I, metatarsus (II ~38 mm, III ~42 mm, IV ~39 mm), phalanx II-1 (~9.5 mm), phalanx II-2 (~10 mm), pedal ungual II, phalanx III-1 (~11 mm), phalanx III-2 (~10.5 mm), phalanx III-3, pedal ungual III, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV, remiges, hindlimb feathers (Heller, 1959)
Early Tithonian, Late Jurassic
Lower Eichstatt Member of the Altmuhltal Formation, Germany
(MB.Av.101; = HMN MB. 1880/81; Berlin specimen; second specimen; holotype of Archaeopteryx seimensii) (.405 m, 340 g; 330 day old juvenile) skull (45 mm), sclerotic ring, mandible (43.5 mm), hyoids, axis (5 mm), third cervical vertebra (6.5 mm), fourth cervical vertebra (9 mm), fifth cervical vertebra (9.5 mm), sixth cervical vertebra (8 mm), seventh cervical vertebra (9 mm), eighth cervical vertebra, ninth cervical vertebra (8 mm), tenth cervical vertebra (7.7 mm), cervical ribs, first dorsal vertebra (7.3 mm), second dorsal vertebra (5.5 mm), third dorsal vertebra (5.9 mm), fourth dorsal vertebra (5.7 mm), fifth dorsal vertebra (5.5 mm), sixth dorsal vertebra (5.5 mm), seventh dorsal vertebra (6.1 mm), eighth dorsal vertebra (6.1 mm), ninth dorsal vertebra (6.3 mm), tenth dorsal vertebra (6.2 mm), eleventh dorsal vertebra (6.2 mm), twelfth dorsal vertebra, thirteenth dorsal vertebra, dorsal ribs, gastralia, (sacrum ~31 mm) first sacral vertebra (6.5 mm), second sacral vertebra, first caudal vertebra, second caudal vertebra (5.3 mm), third caudal vertebra (~4 mm), fourth caudal vertebra (~4 mm), fifth caudal vertebra (6 mm), sixth caudal vertebra (6.5 mm), seventh caudal vertebra (7.3 mm), eighth caudal vertebra (9 mm), ninth caudal vertebra (10.5 mm), tenth caudal vertebra (11.3 mm), eleventh caudal vertebra (11.3 mm), twelfth caudal vertebra (~11.5 mm), thirteenth caudal vertebra (~11.5 mm), fourteenth caudal vertebra (~10.5 mm), fifteenth caudal vertebra (10 mm), sixteenth caudal vertebra (10 mm), seventeenth caudal vertebra (~10 mm), eighteenth caudal vertebra (~9.5 mm), nineteenth caudal vertebra (8.5 mm), twentieth caudal vertebra (8 mm), twenty-first caudal vertebra (7.2 mm), twenty-second caudal vertebra (5.5 mm), scapulae (42 mm; one incomplete), coracoids (one fragmentary), furcular fragments, humeri (63.5 mm), radii (54.4 mm), ulnae (55 mm), scapholunares, pisiforms, semilunate carpals, distal carpal III, metacarpals I (8.3 mm), phalanges I-1 (20.5 mm), manual unguals I (~12.5 mm), metacarpals II (28 mm), phalanges II-1 (15.5 mm), phalanges II-2 (19.4 mm), manual unguals II (~16 mm), metacarpals III (24.8 mm), phalanges III-1 (6.4 mm), phalanges III-2 (4.2 mm), phalanges III-3 (12.3 mm), manual unguals III (~9.5 mm), manual claw sheaths, ilia (~32 mm), pubes (48 mm), ischium (~20 mm), femora (52.2 mm), tibiae (71 mm), astragalus, distal tarsal III, distal tarsal IV, metatarsal I, phalanx I-1 (5.2 mm), pedal ungual I (5.5 mm), partial metatarsal II (~35 mm), phalanx II-1 (8.2 mm), phalanx II-2 (7 mm), pedal ungual II (12.5 mm), incomplete metatarsals III (~37 mm), phalanges III-1 (9.6 mm), phalanges III-2 (9 mm), phalanges III-3 (8.2 mm), pedal unguals III (8.8 mm), incomplete metatarsal IV (~32.5 mm), phalanx IV-1 (7 mm), phalanges IV-2 (6.4, 6.6 mm), phalanges IV-3 (4.9 mm), phalanges IV-4 (5.6, 5.8 mm), pedal unguals IV (6.8 mm), pedal claw sheaths, propatagium, body feathers, remiges, retrices (Haberlein, 1877)
Early Tithonian, Late Jurassic
Upper Eichstatt Member of the Altmuhltal Formation, Germany
(BMMS 500; Solnhofen specimen; sixth specimen; holotype of Wellnhoferia grandis) (1.1 kg, 530 day old subadult) partial skull (~65 mm), sclerotic plates, partial mandible (~61 mm), axis, third cervical vertebra (~9 mm), partial fourth cervical vertebra, cervical ribs, partial eleventh dorsal vertebra, twelfth dorsal vertebra (~8 mm), thirteenth dorsal vertebra (~8 mm), fourteenth dorsal vertebra (8.8 mm), dorsal ribs, gastralia, (sacrum ~28 mm) partial first sacral vertebra, second sacral neural spine, third sacral neural arch, fourth sacral transverse process, fifth sacral neural arch, first caudal vertebra (5.4 mm), second caudal vertebra (6.2 mm), third caudal vertebra (6.7 mm), fourth caudal vertebra (6.5 mm), fifth caudal vertebra (7.5 mm), sixth caudal vertebra (9 mm), seventh caudal vertebra (9.7 mm), eighth caudal vertebra (9.5 mm), ninth caudal vertebra (13 mm), tenth caudal vertebra (14.2 mm), eleventh caudal vertebra (14.3 mm), twelfth caudal vertebra (15.5 mm), thirteenth caudal vertebra (15 mm), fourteenth caudal vertebra (~11 mm), partial fifteenth caudal vertebra (~11 mm), chevrons, incomplete scapulae (~51 mm), coracoids (24.5 mm), partial furcula, incomplete humeri (83 mm), partial radii (~69 mm), partial ulnae (~72 mm), partial metacarpals I, phalanges I-1 (28, 28.4 mm), manual unguals I (17.5 mm), incomplete metacarpals II (~36.6 mm), phalanges II-1 (20.1 mm), phalanges II-2 (27.5 mm), manual unguals II (17.8 mm), incomplete metacarpals III, phalanx III-1 (8 mm), phalanges III-2 (6.5 mm), phalanges III-3 (17.8 mm), manual unguals III (12 mm), manual claw sheaths, ilia (~38 mm), pubes (59.3 mm), partial ischium (~24.5 mm), femora (~67 mm), tibiae (92 mm), fibula (82.4 mm), astragali, calcanea, distal tarsals, metatarsals I (9.9 mm), phalanx I-1 (11 mm), pedal ungual I (~9.8 mm), metatarsus (II 45 mm, III ~47.5 mm, IV 45 mm), phalanges II-1 (12 mm), phalanges II-2 (12.5 mm), pedal unguals II (~14 mm), phalanges III-1 (one proximal; 13.7 mm), phalanx III-2 (11.8 mm), phalanx III-3 (10.5 mm), pedal ungual III (~10 mm), phalanx IV-1 (10 mm), phalanx IV-2 (8.5 mm), phalanx IV-3 (9.5 mm), pedal ungual IV (~12.6 mm), metatarsal V (10.5 mm), pedal claw sheaths, remiges (Wellnhofer, 1988)
(JM SoS 2257; Eichstatt specimen; fifth specimen; holotype of Archaeopteryx recurva) (.29 m, 180 g; 110 day old juvenile) skull (39 mm), sclerotic ring, mandible (36.5 mm), atlas, axis (3.7 mm), third cervical vertebra (~4.5 mm), fourth cervical vertebra (~6 mm), fifth cervical vertebra (~7 mm), sixth cervical vertebra (~5.5 mm), seventh cervical vertebra (~5 mm), eighth cervical vertebra (~5 mm), ninth cervical vertebra (~4.5 mm), tenth cervical vertebra (~3.5 mm), cervical ribs, first dorsal vertebra (4 mm), second dorsal vertebra, partial third dorsal vertebra, partial fifth dorsal vertebra (4 mm), sixth dorsal vertebra (4 mm), seventh dorsal vertebra (~4 mm), eighth dorsal vertebra (4.5 mm), ninth dorsal vertebra (~5 mm), tenth dorsal vertebra (~4.5 mm), eleventh dorsal vertebra, twelfth dorsal vertebra (4 mm), thirteenth dorsal vertebra (4 mm), dorsal ribs, gastralia, (sacrum ~16.5 mm), first sacral centrum (3.7 mm), second sacral centrum (3.4 mm), third sacral centrum (3.1 mm), fourth sacral centrum (3.2 mm), fifth sacral centrum, first caudal vertebra (3 mm), second caudal vertebra (3.3 mm), third caudal vertebra (3.5 mm), fourth caudal vertebra (~4 mm), fifth caudal vertebra (4.7 mm), sixth caudal vertebra (5.4 mm), seventh caudal vertebra (6.4 mm), eighth caudal vertebra (7.2 mm), ninth caudal vertebra (7.9 mm), tenth caudal vertebra (8.4 mm), eleventh caudal vertebra (8.5 mm), twelfth caudal vertebra (8.6 mm), thirteenth caudal vertebra (8.3 mm), fourteenth caudal vertebra (8.3 mm), fifteenth caudal vertebra (8 mm), sixteenth caudal vertebra (7.7 mm), seventeenth caudal vertebra (7.4 mm), eighteenth caudal vertebra (6.9 mm), nineteenth caudal vertebra (6.6 mm), twentieth caudal vertebra (~5.5 mm), twenty-first caudal vertebra (4.2 mm), twenty-second caudal vertebra (4 mm), twenty-third caudal vertebra, seventeen chevrons, incomplete scapulae, partial coracoids, humeri (41.5 mm), radii (35 mm), ulnae (36.5 mm), scapholunares, pisiform, semilunate carpals, distal carpals III, metacarpals I (one proximal; 5.5 mm), phalanges I-1 (one distal; 15.6 mm), manual unguals I (9.8 mm), metacarpals II (one incomplete; 17.8 mm), phalanges II-1 (10.2 mm), phalanges II-2 (15.1 mm), manual unguals II (10.8 mm), metacarpals III (one incomplete; 16.5 mm), phalanx III-1 (4.2 mm), phalanx III-2 (3 mm), phalanx III-3 (9.8 mm), manual unguals III (6.5 mm), manual claw sheaths, incomplete ilium (~20 mm), pubes (31.5 mm), ischia (14.5 mm), femora (37 mm), tibiae (~53 mm), fibula (50.5 mm), astragali, distal tarsal III, distal tarsal IV, metatarsals I, phalanges I-1 (5.5 mm), pedal unguals I (3.5 mm), partial metatarsals II (28.3 mm), phalanges II-1 (~7.1 mm), phalanges II-2 (7 mm), pedal unguals II (5.8 mm), metatarsals III (30.2 mm), phalanges III-1 (one proximal; 9 mm), phalanges III-2 (8 mm), phalanges III-3 (7 mm), pedal unguals III (5.4, 4.8 mm), metatarsals IV (27.3 mm), phalanges IV-1 (6.1 mm), phalanges IV-2 (5 mm), phalanges IV-3 (4.6, 4.7 mm), phalanges IV-4 (4.9 mm), pedal unguals IV, metatarsals V (one partial; 6.5 mm), pedal claw sheaths, remiges, retrices (Wellnhofer, 1974)
(WDC-CSG-100; Thermopolis specimen; tenth specimen) (260 g, 1 year old juvenile) skull (52.9 mm), sclerotic ring, mandibular fragment, five dentary teeth, partial hyoid, six cervical vertebrae, partial seventh dorsal vertebra, partial eighth dorsal vertebra, partial ninth dorsal vertebra, partial tenth dorsal vertebra, partial eleventh dorsal vertebra, partial twelfth dorsal vertebra, partial thirteenth dorsal vertebra, dorsal ribs, gastralia, first sacral centrum, second sacral centrum, third sacral centrum, fourth sacral centrum, fifth sacral fragment, first caudal vertebra, second caudal vertebra (3.8 mm), third caudal vertebra (4.2 mm), fourth caudal vertebra (4.2 mm), fifth caudal vertebra (5.4 mm), sixth caudal vertebra (6.5 mm), seventh caudal vertebra (7.9 mm), eighth caudal vertebra (9.5 mm), ninth caudal vertebra, tenth caudal vertebra (~10 mm), eleventh caudal vertebra (11.1 mm), twelfth caudal vertebra (10.9 mm), thirteenth caudal vertebra (10.9 mm), fourteenth caudal vertebra (10.6 mm), fifteenth caudal vertebra (10.6 mm), sixteenth caudal vertebra (10.1 mm), seventeenth caudal vertebra (9.1 mm), eighteenth caudal vertebra (9.1 mm), nineteenth caudal vertebra, partial twentieth caudal vertebra, chevrons, scapulae (35 mm), coracoids, furcula, humeri (one proximal; 56.9), radii, ulnae (50.9 mm), semilunate carpal, metacarpals I (6.6 mm), phalanges I-1 (19.5 mm), manual unguals I, metacarpals II (23.5 mm), phalanges II-1 (12.8 mm), phalanges II-2 (18.6 mm), manual unguals II, metacarpals III (22 mm), phalanges III-1 (4.8 mm), phalanges III-2 (4.2 mm), phalanges III-3 (12.9 mm), manual ungual III, manual claw sheaths, partial ilium, pubes, ischium, femora (one incomplete; 50.3 mm), tibiae (one incomplete; 74.6 mm), fibula, astragali, calcaneum, metatarsals I, phalanges I-1 (6.1 mm), pedal unguals I, metatarsals II (35.1 mm), phalanges II-1 (10.6 mm), phalanges II-2 (one proximal; 8.8 mm), pedal ungual II, metatarsals III (39.6 mm), phalanges III-1 (one proximal; 10.8 mm), phalanx III-2 (9.6 mm), phalanx III-3 (7.8 mm), pedal ungual III, metatarsals IV (36.3 mm), phalanges IV-1 (7.5 mm), phalanges IV-2 (one proximal; 6.6 mm), phalanx IV-3 (5.6 mm), phalanx IV-4 (5.6 mm), pedal ungual IV, pedal claw sheaths, remiges, retrices (Mayr et al., 2005)
(Pohl coll; on long term loan to BSP; Altmuhl specimen; eleventh specimen) premaxillae, jugal, dentaries, partial ?splenial, incomplete ?surangular, ?articular, axis, third cervical vertebra, fourth cervical vertebra, fifth cervical vertebra, sixth cervical vertebra, seventh cervical vertebra, eighth cervical vertebra, ninth cervical vertebra, tenth cervical vertebra, cervical ribs, first dorsal vertebra, second dorsal vertebra, third dorsal vertebra, fourth dorsal vertebra, fifth dorsal vertebra, sixth dorsal vertebra, seventh dorsal vertebra, eighth dorsal vertebra, ninth dorsal vertebra, tenth dorsal vertebra, eleventh dorsal vertebra, twelfth dorsal vertebra, thirteenth dorsal vertebra, dorsal ribs, gastralia, partial sacrum, first caudal vertebra, second caudal vertebra, third caudal vertebra, fourth caudal vertebra, fifth caudal vertebra, sixth caudal vertebra, eighth caudal vertebra, ninth caudal vertebra, tenth caudal vertebra, eleventh caudal vertebra, twelfth caudal vertebra, thirteenth caudal vertebra, fourteenth caudal vertebra, fifteenth caudal vertebra, sixteenth caudal vertebra, seventeenth caudal vertebra, eighteenth caudal vertebra, nineteenth caudal vertebra, twentieth caudal vertebra, twenty-first caudal vertebra, chevrons, scapula (44.4 mm), incomplete coracoid (13.3 mm), partial furcula, incomplete humerus (65.6 mm), radius (~62 mm), ulna (~62.5 mm), pisiform, semilunate carpal, partial metacarpal I (~9.9 mm), phalanx I-1 (23.3 mm), manual ungual I, metacarpal II (~31.5 mm), phalanx II-1 (18.6 mm), phalanx II-2 (19.6 mm), manual ungual II, metacarpal III (~31.5 mm), phalanx III-1 (6.4 mm), phalanx III-2 (5.3 mm), phalanx III-3 (~12.3 mm), manual ungual III, manual claw sheaths, incomplete ilium (~37.1 mm), pubes (52.2 mm), ischium (23.3 mm), femora (one distal; 55.3 mm), tibiae (76.3 mm), partial fibulae, astragali, metatarsals I (~7.1 mm), phalanges I-1 (7.9, 7.4 mm), pedal unguals I, metatarsals II (36.8, 38.4 mm), phalanges II-1 (9.9, 9.9 mm), phalanges II-2 (9.7, 9.5 mm), pedal unguals II, metatarsals III (40.3, 41.4 mm), phalanges III-1 (11.6, 11.2 mm), phalanges III-2 (10 mm), phalanges III-3 (8.8 mm), pedal unguals III, metatarsal IV (~37.9 mm), phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal unguals IV, pedal claw sheaths, body feathers, remiges, retrices (Ravasz, online 2011; described by Foth et al., 2014)
Early Tithonian, Late Jurassic
Mörnsheim Formation, Germany
(SNSB BSPG VN-2010/1; Daiting specimen; The Phantom; eighth specimen; holotype of Archaeopteryx albersdoerferi) (320 day old juvenile) incomplete skull, mandibles (one incomplete, one partial), scapulae (35.5 mm), incomplete coracoids, furcula, humeri (one incomplete; 55.5 mm), radius (46.7 mm), ulna (47.5 mm), scapholunare, pisiform, incomplete carpometacarpus, phalanx I-1, partial manual ungual I, proximal femur, fibular fragment (Mauser, 1997)
Early Tithonian, Late Jurassic
Painten Formtion, Germany
(Dinosaurier Freiluftmuseum Altmuhltal coll.; DNWK 02924; Schamhaupten specimen; twelfth specimen) skull (56 mm), mandibles (45.5 mm), mid cervical vertebra, eighth cervical vertebra (8.1 mm), ninth cervical vertebra (6.1 mm), tenth cervical vertebra (5.3 mm), first dorsal vertebra, second dorsal vertebra, third dorsal vertebra, fourth dorsal vertebra, fifth dorsal vertebra, sixth dorsal vertebra (6.2 mm), seventh dorsal vertebra (6.2 mm), eighth dorsal vertebra (6 mm), ninth dorsal vertebra (6 mm), tenth dorsal vertebra, eleventh dorsal vertebra, twelfth dorsal vertebra, thirteenth dorsal vertebra, dorsal ribs, gastralia, partial sacrum, proximal caudal vertebrae, fourth caudal vertebra (~5.8 mm), fifth caudal vertebra (~6.1 mm), sixth caudal vertebra (6.2 mm), seventh cuadal vertebra (7.5 mm), eighth caudal vertebra (9 mm), ninth caudal vertebra (9.7 mm), tenth caudal vertebra (9.9 mm), eleventh caudal vertebra (10.1 mm), twelfth caudal vertebra (10.1 mm), thirteenth caudal vertebra (9.9 mm), fourteenth caudal vertebra (9.9 mm), fifteenth caudal vertebra (9.7 mm), sixteenth caudal vertebra (9.3 mm), seventeenth caudal vertebra (9 mm), eighteenth caudal vertebra (8.7 mm), nineteenth caudal vertebra (6.8 mm), twentieth caudal vertebra (5.3 mm), twenty-first caudal vertebra (3.2 mm), twenty-second caudal vertebra (2.4 mm), chevrons, scapulae (43 mm), coracoid, incomplete furcula, humeri (61 mm), radii (54.4 mm), ulnae (55 mm), semilunate carpal, metacarpals I (6.8 mm), phalanges I-1 (20.7 mm), manual unguals I (9.4 mm), metacarpals II (28.2 mm), phalanges II-1 (16 mm), phalanges II-2 (19.3 mm), metacarpals III (27.2 mm), phalanges III-1 (7.1 mm), phalanges III-2 (4.6 mm), phalanges III-3 (12 mm), manual unguals III (7.5 mm), manual claw sheaths, incomplete pubes, incomplete ischium, incomplete femora (~53 mm), tibiae (66 mm), fibulae, astragalus, calcaneum, distal tarsal IV, metatarsals I (8.2 mm), phalanges I-1 (7 mm), pedal unguals I (6.3 mm), metatarsals II (31.6 mm), phalanges II-1 (8.4 mm), phalanges II-2 (8.3 mm), pedal unguals II (9.8 mm), metatarsals III (34 mm), phalanges III-1 (10.5 mm), phalanges III-2 (9.2 mm), phalanges III-3 (8 mm), pedal unguals III (8.1 mm), metatarsals IV (33.1 mm), phalanges IV-1 (7.3 mm), phalanges IV-2 (6.5 mm), phalanges IV-3 (5.8 mm), phalanges IV-4 (5.9 mm), pedal unguals IV (6.2 mm), pedal claw sheaths, metatarsals V (Rauhut, Foth and Tischlinger, 2018)
Diagnosis- (after Elzanowski, 2002) 8-9 maxillary teeth (also in Dromaeosaurus); premaxillary and anterior dentary teeth have the basal third to half of the crown with straight to slightly convex mesial and distal margins that slightly converge apically, before the apical part of the crown forms a bulbous mesial and less marked distal expansion.
(after Rauhut et al., 2018) marked incision between the postorbital and quadratojugal processes of the jugal (also in Microraptor); depressed rim around the posterior margin of the trigeminal foramen (unknown in other archaeopterygids).
(after Kundrát et al., 2019) anterior-most extension of promaxillary fenestra situated between fifth and sixth maxillary teeth; 10-12 dentary teeth.
Other diagnoses- Elzanowski (2002) listed several characters of his Archaeopterygidae that are plesiomorphic (four premaxillary teeth; premaxilla projects anterior to mandible; 23 presacral vertebrae; five sacral vertebrae; no hypocleidium on furcula). An absent external mandibular fenestra is probably true in other archaeopterygids, a mid dorsal ischial process is common in basal paravians.
Rauhut et al. (2018) note 'a longitudinal groove on the medial side of the suborbital process' of the jugal is also present in Anchiornis, so this is an archaeopterygid character. Similarly, they state 'quadratojugal process of the jugal very slender, less than half the height of the minimal height of the suborbital process' is present in Anchiornis, Xiaotingia and Microraptor. The presence of 'nine cervical and fourteen dorsal vertebrae' is left uncertain here given the poor preservation of Archaeopteryx' cervicodorsal vertebrae and the condition in related taxa.
London specimen and feather- Meyer (1861a) first mentioned and described a feather (BSP 1869 VIII 1; MB.Av.100) discovered in Spring or Summer 1861 (published August 16th), but did not name it. Wellnhofer (2009) notes that a discovery in 1860 is sometimes reported but that there is no evidence it was that long prior to the September 15 publication of Meyer 1861a. Meyer later (1861b) referred to the feather and mentioned the then undescribed London specimen noticed in Haberlein's collections the Summer of that year, stating that "For the denomination of the animal I consider the term Archaeopteryx lithographica as appropriate", but exactly which specimen (if not both) he considered "the animal" is ambiguous. The title suggests the feather is the holotype, but this was written by an anonymous editor. In his later (1862a) paper, he indicates the name Archaeopteryx lithographica was meant to be tied to the feather, making it the holotype ("The fossil feather presented by me may come from a similar animal, for which I have chosen the denomination Archaeopteryx lithographica"). This was misunderstood by many subsequent authors, including de Beer (1954), who have viewed the London specimen as the holotype instead. Wagner (1962a) described the London specimen as a new genus of pterosaur- Griphosaurus, as Meyer's 1861b paper had not been published at the time of Wagner's presentation (November 9, 1861). While Wagner's paper was dated 1861, it wasn't published until January 20th, 1862 (Swinton, 1960), but an English translation was published in April 1862 (Wagner, 1862b). Woodward (1962) used the name Archaeopteryx lithographica, but stated Owen would describe the London species under the name Griphornis longicaudatus. A footnote indicates Owen had decided to retain the name Archaeopteryx though, as indeed did happen in his 1863 paper. More confusingly, Woodward uses the name "Griphosaurus problematicus Wagner, 1861" in the plate label for the London specimen, though Wagner never used a species name in his 1862 ("1861") publication. Owen (1863a) made the London specimen the holotype of his new species Archaeopteryx macrura (misspelled macrurus in his 1863a publication, but corrected in 1863b), since he considered its feathers different from the A. lithographica holotype. Several later authors followed Owen's usage (Dames, 1884; Lambrecht, 1933). The new combination Griphosaurus longicaudatus has been listed as deriving from Owen (1862), but Bühler and Bock (2002) indicate this was a mistaken attribution by Brodkorb (1963). Petronievics (1921) used the name Archaeopteryx oweni for the London specimen without justification, so it is clearly a junior synonym. In 1960, Swinton petitioned the ICZN to place Archaeopteryx lithographica on the Official List of Generic/Specific Names in Zoology, and to add Griphosaurus, Griphornis longicaudatus, Griphosaurus problematicus, Archaeopteryx macrurus and Archaeopteryx oweni to the Official Index of Rejected and Invalid Generic/Specific Names in Zoology, which was upheld by Riley and China in 1961 as Opinion #607. Eisenmann (1974) in a comment to the ICZN proposed ruling the London specimen is the type of Archaeopteryx lithographica, but the issue was not taken up by the commission at the time. Bock and Bühler (2007) petitioned the ICZN to make the London specimen the neotype of Archaeopteryx lithographica, since authors have interpreted Meyer's intent in different ways, and nearly all references have based the taxon on the more diagnostic skeleton as opposed to the feather. Kadolsky (2008) further noted "the skeleton find (the later BMNH specimen no. 37001) is not described, diagnosed or characterised by even a single word, nor is an indication to such characterisation given" so that Archaeopteryx lithographica the London specimen would be a nomen nudum if based on this publication, so asked the ICZN "to use its plenary power to rule that both the generic and specific names Archaeopteryx and lithographica have been made available by von Meyer, 1861b." The issue was decided by the ICZN in 2011 as Opinion 2283 in favor of making the London specimen the neotype. The London specimen was most recently described in detail by de Beer (1954).
The feather- The feather was redescribed by Griffiths (1996), who noted it differed from the London and Berlin specimens in being smaller, broader and more asymmetric. He proposed that both taphonomic and taxonomic explanations were possible, and his analysis indicates the feather cannot be definitively referred to Archaeopteryx lithographica. Benton and Gower (2002) reveal Walker had written a letter in 1985 also wondering about the possibility the feather was taxonomically distinct from the skeletons, though it was never published. The feather was reinterpreted as a retrix by Foth and Rauhut (2013) and by Kaye et al. (2019) as a secondary much shorter than Archaeopteryx'. Most recently, Carney et al. (2019; published in detail in 2020) convincingly argued the feather is an upper major primary covert and found it was identical in anatomy and size to that of the Altmuhl Archaeopteryx specimen. Unfortunately they dismissed an alternative taxonomic identification by proposing all Solnhofen paravians are Archaeopteryx, whereas this site supports the validity of 'anchiornithine' Ostromia and unenlagiine Alcmonavis. Yet given the differences between Archaeopteryx and Anchiornis feathers, and that unenlagiines are even more distant phylogenetically, a referral to Ostromia or the larger Alcmonavis is here considered less likely.
Berlin specimen- The Berlin specimen was probably discovered in 1875 or 1874 (Tischlinger, 2005), though first announced in May 1877 (Haberlein, 1877) and variously regarded as conspecific with the London specimen (Dames, 1884), or different due to size (Seeley, 1881). Later, Dames (1897) made the holotype of a new species- Archaeopteryx siemensii due to dental and pelvic characters. Subsequently, Petronievics (as a footnote in Petronievics and Woodward, 1917) separated it further as a new genus- Archaeornis. This was due to his view the expanded calcitic mass of the London specimen was not homologous to the pubic boot of the Berlin specimen, that the latter lacked a pubic symphysis, and other unstated pectoral and pelvic differences. Additional differences later provided by Petronievics (1921, 1925) include teeth with a circular cross section, proximal carpals ossified, metacarpal III with cylindrical section, unfused scapulocoracoid, narrow coracoid, unfused tibiotarsus, pubis and ischium at a greater angle, obturator foramen absent in pubis, straight ischium, and ischium poorly ossified distally. Petronievics later (1927, 1950) went so far as to place Archaeopteryx as a pan-paleognath and Archaeornis as a pan-neognath. Nopcsa (1923) stated most of these characters were preservational (carpal number; pubic foot size; ischial shape) or ontogenetic (length of pubic symphysis; ischial ossification; tibiotarsal fusion), while others were misinterpretations (tooth cross section; scapulocoracoid fusion; pubic angle; obturator foramen). He and de Beer (1954) synonymized it with A. lithographica, which has been the consensus until the 2000s. In 2002, Elzanowski reinstated Archaeopteryx siemensii based on the smaller size, lack of a cuppedicus fossa on the ilium, lack of a ventral hook on the ilial preacetabular process, and pedal unguals without flexor tubercles. Senter and Robins (2003) disagreed, finding flexor tubercles in all Archaeopteryx specimens, and believing the ilial features to become more developed with age. Mayr et al. (2007) confirmed the flexor tubercles are more poorly developed and noted the metatarsus was more slender, but did not comment on ilial morphology. Wang et al. (2017) confirmed the presence of a propatagium.
Maxberg Specimen- The Maxberg specimen was discovered in 1956 and described in 1959 by Heller. It was privately owned by Opitsch, though on display at the Maxberg Museum from 1959-1982. Unfortunately, when Opitsch died in 1991, the specimen could not be found and was seemingly stolen (Abbott, 1992). Mayr et al. (2007) assigned it to A. lithographica (as opposed to A. siemensii) due to its robust metatarsus.
Eichstatt specimen- The Eichstatt specimen was recognized in March 1951 and originally identified as a juvenile Compsognathus. It was initially described by Mayr (1973) as perhaps a new species of Archaeopteryx, and later in detail by Wellnhofer (1974) as a juvenile A. lithographica. Howgate (1984) separated it from the other specimens then known as a new species, Archaeopteryx recurva. This was based on the small size, recurved teeth, supposedly absent furcula, more vertical pubis, short pubic symphysis, elongate tibia (1.42 times femoral length compared to 1.30-1.38), elongate metatarsus (1.67 times femoral length compared to 1.43-1.47) and unfused metatarsus. He later used these characters to separate it further as a new genus- Jurapteryx. However, almost all later authors have believed it to be a juvenile specimen of Archaeopteryx lithographica (Paul, 1988; Wellnhofer, 1992), with the furcula missing due to taphonomy and the pubes of the London and Berlin specimens rotated too far posteriorly. Houck et al. (1990) determined the limb proportions of Archaeopteryx specimens were consistant with allometric variation that would be expected due to ontogeny, which has been confirmed for subsequent specimens by Senter and Robins (2003) and Bennett (2008). Christiansen's (2006) allometric study concluded the data supported multiple species at least as well as it did a single species, but his rationale was flawed (Bennett, 2008). Elzanowski (2002) could not confirm separation of the Eichstatt specimen as a distinct species, while Senter and Robins (2003) noted theropods such as Coelophysis decrease curvature of teeth with ontogeny, suggesting the same explanation for the Eichstatt specimen's teeth.
Solnhofen specimen- The Solnhofen specimen was recognized as Archaeopteryx in November 1987 in Muller's private collection after being initially identified as a Compsognathus until it was examined by Wellnhofer and described by him in 1988 as a new specimen of Archaeopteryx lithographica. Muller claimed it was probably recovered 10-15 years prior to 1987, but a litigant onvolved in ownership of the fossil claimed it was actually found in 1985. Longer descriptions of the material appeared later in 1988 and in 1992. In 2001, Elzanowski separated the specimen as a new taxon - Wellnhoferia grandis. This was based on the large size, short tail as reconstructed (~16-17 vertebrae), unfused scapulocoracoid, shorter manual ungual I compared to phalanx I-1 (33%), manual phalanges I-1 and II-2 deeper, manual phalanges III-1 and III-2 sutured, more retroverted pubis (~128 degrees), metatarsals II and IV subequal in length, pedal phalanx II-2 longer than II-1, short pedal digit IV with only four phalanges, pedal ungual IV longest phalanx in digit, and pedal ungual IV straight with flexor tubercle widely separated from its base. In 2002, he added a proximally tapering metatarsal II to the diagnosis. Senter and Robins (2003) agree it is distinct, and Mayr et al. (2007) agree it is distinct from the Berlin and Munich specimens, but disputed differences between it and the London specimen (synonymizing it with A. lithographica). In particular, they note the proportions of manual digit I phalanges and number of phalanges in pedal digit IV are not preserved in the London specimen, and the tail length is uncertain in the Solnhofen specimen (it was estimated to be short by Elzanowski due to the rapid decrease in central length distally). The specimens are also both larger than other specimens and share additional characters (premaxillary teeth with constricted crowns; similar limb proportions; stout metatarsus; well developed flexor tubercles on pedal unguals). However, the London specimen has a fused scapulocoracoid, pedal phalanx II-2 equal in length to II-1, a more elongate pedal digit IV, and a curved pedal ungual IV.
Munich specimen- The next specimen was discovered on August 3 1992 and first called the Solnhofen-Aktien-Verein specimen, then later the Munich specimen. It was described in 1993 as a new species of Archaeopteryx, A. bavarica. This was based on the small size, twelve dentary teeth, dentary interdental plates, ossified sternum, elongate tibia (1.48 times femoral length), hindlimb elongate compared to humerus (3.56 times). Elzanowski (2002) added further distinguishing characters- anterior dentary tooth crowns compressed; third and fourth cervical neural spines tall, equaling about a third of vertebral height; ulna elongate compared to humerus (96%); ilium lacking ventral hook on preacetabular process; no cuppedicus fossa on ilium; pedal unguals lack flexor tubercles. Senter and Robins (2003) determined the tibial, hindlimb and ulnar lengths were all explainable by allometry, believed the ilial features could be absent due to ontogeny, noted tooth compression could be too (as in tyrannosaurids), and stated pedal ungual flexor tubercles are actually present. Wellnhofer and Tischlinger (2004) determined the supposed sternum of the Munich specimen is really a coracoid. Mayr et al. (2007) noted their new specimen is intermediate between the Munich and Berlin specimens in size, hindlimb and ulnar proportions, while its tibia is longer than the Munich specimen. Considering the misidentified sternum, and that the ilial and pedal ungual characters are supposedly shared with the Berlin specimen, they synonymized A. bavarica with A. siemensii.
Daiting specimen- The eighth or Daiting specimen was discovered in 1990 and initially identified as a pterosaur, but not publicized until a cast was displayed in 1996. It was originally noted by Mauser (1997) in a brief article and was described by Tischlinger (2009) then in more detail by Kundrát et al. (2019). Albersdörfer bought it from a private collector in 2009 and placed it on long term loan to the BSPG as SNSB BSPG VN-2010/1. It is the youngest of described specimens, the same age as Alcmonavis. Kundrát et al. (2014) believed fused internasal and interfrontal contacts and "numerous other cranial features" suggested this could be a separate species from the Eichstatt and Thermopolis specimens, and described it as Archaeopteryx albersdoerferi in 2019. Diagnostic characters listed by Kundrát et al. are- angle between the nasal process and ventral margin of maxilla >50 degrees; antorbital fenestra and combined maxillary/promaxillary fenestrae both higher than wide; anterior lacrimal process slightly longer than posterior process; pneumatic recess present at anterior end of jugal; incomplete postorbital bar; Y-shaped quadratojugal with reduced dorsal process and expanded posterior process; quadrate with incompletely bilobed head, massive lateral vertical rim and enlarged medial condyle separated from lateral condyle by shallow depression; maxillary and pterygoid palatine processes of equal length; heterodont maxillary dentition comprising asymmetrical anterior and symmetrical posterior crowns; teeth labiolingually compressed; coracoid with lateral process as long as half of mid-coracoid width; coracoid with tuber that does not project beyond dorsal margin; deltopectoral portion of humeral shaft strongly angled (rather then curved) posteriorly; distal carpal III fused with metacarpal II; semilunate carpal fused with the metacarpals I and II. It was recovered as either an archaeopterygid (Xu et al. 2011 TWiG parsimony analysis; Godefroit et al. 2011 Cau analysis) or closer to Aves (Xu et al. 2011 TWiG Bayesian analysis; Turner et al., 2012 TWiG analysis).
New specimens- The ninth specimen was initially announced by Roper (2004) after it was collected in Spring of that year. Also known as the chicken wing or Ottmann and Steil specimen, it has immature bone grain. Wellnhofer and Roper (2005) described it in detail, assigning it to A. lithographica instead of A. bavarica (based on ulnar proportions).
The Thermopolis specimen was found in the estate of a fossil collector in the 1970s, but not offered to the scientific community until 2001. It was briefly described in 2005 (Mayr, 2005; Mayr et al., 2005) before being described in detail by Mayr et al. (2007). Though initially only assigned to Archaeopteryx sp. (Mayr et al., 2005), they later assigned it to A. siemensii, in which they also include the Munich specimen. This was based on small size, slender metatarsus, poorly developed pedal ungual flexor tubercles, as well as characters differing from the Solnhofen specimen (long manual ungual I; metatarsals II and IV not subequal; pedal digit IV with five phalanges; pedal ungual IV shorter than phalanx IV-1). They further note that the ischium exhibits a different morphology than the London specimen, which added evidence to separate siemensii from lithographica.
An eleventh specimen or Altmuhl specimen was announced at the Munich Show - Mineralientage München in 2011 (artdaily.cc, online 2011). The skeleton is essentially complete except for most of the skull and one pectoral girdle and arm. Foth and Rauhut (2013) describe the feathers in an abstract, and officially in Foth et al. (2014). Foth et al. only refer the specimen to Archaeopteryx sp. noting the taxonomic controversy surrounding the genus.
The twelfth specimen or Schamhaupten specimen was found in Summer of 2010 and described in depth by Rauhut et al. (2018). It is the oldest of published specimens, from the earliest Tithonian Painten Formation, and was referred to Archaeopteryx sp.. It's notable for having obvious postorbitals and prefrontals.
A thirteenth specimen, SNSB-BSPG 2017 I 133 or the Muhlheim specimen, was found in 2017. It was described by Rauhut et al. (2019) as a new taxon of avialan closer to Pygostylia, Alcmonavis poeschli.
Resolving the species problem- As can be seen from the above discussions, recent papers have placed the known specimens in one (Paul, 2002), two (Senter and Robins, 2004; Mayr et al., 2007) or four (Elzanowski, 2002) species, often based on similar characters. These will be examined below (minus the twelfth specimen, described after text was written) to determine how many species are based on good evidence.
Size is not evidence of multiple species, as no specimen is obviously adult, and young theropods (including basal birds) were precocial in regard to their ossification timing (e.g. Scipionyx, juvenile Yixian enantiornithines). The latter disproves Howgate's (1984) suggestion that well ossified elements indicate the Eichstatt specimen is an adult. More recently, Erickson et al. (2009) have analyzed the histology of the Munich specimen and noted this and other specimens (including the Solnhofen specimen) show fibrous surface texture with long striae on long bones typical of young individuals.
Tooth recurvature is polymorphic in every specimen (Howgate, 1984). In the London specimen, the third premaxillary tooth and maxillary teeth 1, 3 and 6 are straight, but an isolated premaxillary tooth is recurved. In the Berlin specimen, the first premaxillary tooth, and maxillary teeth 1 and 6 are straight, but premaxillary teeth 2-4 and maxillary teeth 1 and 3-5 are recurved. In the Eichstatt specimen, maxillary teeth 3 and 9, and dentary teeth 2, 4-6 and 10-11 are straight, but all premaxillary teeth, maxillary teeth 1-2 and 4-6, and dentary tooth 7 are recurved. In the Thermopolis specimen, premaxillary teeth 1-2 are straight, but premaxillary teeth 3-4 and maxillary teeth 4-8 are recurved. In the Solnhofen specimen, premaxillary teeth 1-2 and 4, maxillary teeth 4-7 and perhaps four dentary teeth (4-7?) are straight, but premaxillary tooth 3 and maxillary teeth 2 and 3 are recurved. In the Daiting specimen, three maxillary teeth and two dentary teeth are straight, while one dentary tooth is recurved. In the 11th specimen, premaxillary teeth 1-2 and most dentary teeth are straight but premaxillary teeth 3-4 and at least one dentary tooth are recurved. The narrow tips of the Eichstatt specimen's teeth are directly due to the more acute angle of a recurved crown, and some of its teeth (e.g. second premaxillary tooth) have apical wear facets as in the London specimen. The London's and Munich's specimens teeth appear flatter because they are exposed in lingual view, unlike the Berlin specimen. The presence of one less dentary tooth in the Munich specimen compared to the Eichstatt specimen is within the normal range of interspecific variation in theropods (e.g. Currie, 2003). The presence of interdental plates in the Munich specimen is probably a misinterpretation (Martin and Stewart, 1999), so it it similar to the London and 11th specimens in this regard. So the only difference is in the frequency of tooth recurvature, which is actually less in the Eichstatt specimen than the Berlin and Thermopolis specimens, while the sample size of the London specimen (four teeth) is too low for useful comparison. A large sample of Saurornitholestes teeth shows generally decreasing curvature with increasing size, which shows curvature could be ontogenetic as described by Howgate (1984) for Varanus and Senter and Robins (2004) for Coelophysis. There are a number of cranial differences between the Berlin and Eichstatt specimens which may be due to ontogeny (the Berlin specimen has a more convex ventral maxillary edge, differently sized and placed maxillary fenestrae, deeper dentary; similar to ontogenetic changes in tyrannosaurids), though if the subnarial nasal process being absent isn't preservational, it may be of taxonomic importance. The convexity doesn't seem to be shared by the Solnhofen or Thermopolis specimens. The Thermopolis specimen has a nasal subnarial process and maxillary fenestrae that resemble the Eichstatt specimen's more, but the latter are still differently shaped.
The neural spines of cervical vertebrae three and four are comparable in height in the Eichstatt (3rd 28% of vertebral height; 4th 28%), Berlin (3rd 29%; 4th 28%) and Munich (3rd 29%; 4th 30%) specimens. While it's true the tail of the Solnhofen specimen is broken through the fifteenth caudal, and thus the total number of vertebrae is uncertain, Elzanowski (2001) based his lower estimate on the sharp decrease in centrum length between the thirteenth and fourteenth caudal (the latter is 73% of the former). This compares to 95% in the London specimen, 92% in the Munich specimen, ~91% in the Berlin specimen, 100% in the Eichstatt specimen, 97% in the Thermopolis specimen and ~97% in the 11th specimen. Contrary to Elzanowski though, the fifteenth caudal is not necessarily as short, since only the proximal half is preserved. Other Archaeopteryx specimens can have isolated shorter vertebrae before the tail tip, for instance caudal 17 of the Munich specimen is 74% as long as caudal 16, even though caudals 18 and 19 are 88% and 105% as long as caudal 16. While Elzanowski argues the sudden thinness of these last two vertebrae shows they were near the tail tip, Wellnhofer (1992) notes the tail is twisted at caudals 12-13 to show the following vertebrae in dorsal aspect. As in the Thermopolis specimen, distal caudal vertebrae are taller than they are wide, explaining the thinness. Thus the tail of the Solnhofen specimen was not necessarily shorter than the others'. One vertebral difference in specimens that does seem real is the height of the dorsal neural spines, which using the twelfth dorsal vertebra for comparison are 28% of vertebral height in the Eichstatt specimen, 26% in the Solnhofen specimen, 38% in the Munich specimen, ~29% in the Berlin specimen, ~29% in the Maxberg specimen and ~38% in the 11th specimen. Also, the Thermopolis specimen has its last dorsal sutured to the sacrum, giving it six sacral vertebrae. This is certainly not the case for the Eichstatt, Maxberg and London specimens, and doesn't seem to be for the Munich specimen either. The Eichstatt specimen seems to lack caudal neural spines, wheras they are present in the Munich, Solnhofen and 11th specimens.
The scapula and coracoid are apparently fused in the London specimen, tightly connected in the Berlin and Maxberg specimens, and more loosely connected in the Eichstatt, Solnhofen, Daiting and 11th specimens. They are also unfused in the Munich and Thermopolis specimens. However, scapulocoracoid fusion is variable within other taxa as well, including Struthiomimus, Dromiceiomimus and Caudipteryx. Maniraptoran coracoids are complex bones, which makes comparing their shapes difficult. For instance, the right coracoid of the Thermopolis specimen and left coracoid of the London specimen (as illustrated by Ostrom, 1976) appear to be short, but that's probably because their proximal portion is bent into the sediment. The proximal portion is illustrated in the London specimen by Petronievics and Woodward (1917), and also makes the coracoid elongate in the Munich specimen, while the bend can be observed in the lateral views of the Solnhofen and Thermopolis left coracoids. The medial margin of the London specimen's coracoid has two notches which are not seen in the Munich or Thermopolis specimens. The absence of a furcula in the Eichstatt specimen is near certainly taphonomic, while the supposed sternum in the Munich specimen is a coracoid.
Ulnohumeral ratios vary between ~86% (Maxberg), 87% (Berlin), ~87% (Solnhofen), 88% (Eichstatt and ninth), 89% (Thermopolis), 90% (London), ~92% (Daiting), ~95% (11th) and ~96% (Munich). While this a large amount of variation, is is continuous and also known in Sapeornis. All specimens probably had four carpals (scapholunare, pisiform, semilunate carpal, distal carpal III), though these are easily lost. In particular, the London specimen is seemingly missing proximal carpals, the Eichstatt specimen lacks the pisiform on the right hand (the bone labeled as an ulnare is probably distal carpal III), the left manus of the Munich specimen lacks the scapholunare, only the semilunates are visible in the Thermopolis specimen, ninth and Daiting specimens, and the Maxberg specimen seems to lack preserved carpals. Contrary to Elzanowski (2001), manual ungual I is not short compared to phalanx I-1 in the Solnhofen specimen. However, manual phalanx I-1 of the Solnhofen specimen is 1.39 times as long as phalanx II-1, compared to 1.36 times in the ninth specimen, 1.60 times in the Munich specimen, 1.32 times in the Berlin specimen, 1.53 times in the Eichstatt specimen, 1.52 times in the Thermopolis specimen and 1.25 times in the 11th specimen. Similar variation is known in other coelurosaurs however (Sapeornis, Dromiceiomimus, Gorgosaurus). Elzanowski (2001) noted manual phalanx I-1 is more robust in the Solnhofen and Haarlem specimens (minimum height 8.4% and 8.2% of phalanx length respectively compared to the Berlin (6%), Eichstatt (5.84%) and Munich (5.75%) specimens, and this is also true compared to the ninth (6.56%), Thermopolis (7.4%) and 11th (7.0%) specimens. Yet the latter three also close the gap in ratios, making them seem less important for dividing specimens. Similarly, the Thermopolis specimen (~8.1%) fills the gap between the Solnhofen (8.9%) and 11th (8.7%) on one hand, and the Berlin (6.2%), Eichstatt (6.9%) and Berlin (6.2%) specimens on the other when it comes to robusticity of manual phalanx II-2. The cross section of metacarpal III was said to distinguish the London and Berlin specimens, but this has not been studied in further specimens. Metacarpal III is more bowed with an intermetacarpal gap in the Solnhofen, Munich, Thermopolis and ninth specimens compared to the Berlin, Eichstatt, Daiting and 11th specimens, but this may be due to its orientation. Manual phalanges III-1 and III-2 are sutured in the Solnhofen specimen (as in Jinfengopteryx and the Didactylornis type), but not in the Berlin, Maxberg, Eichstatt, Munich, ninth and Thermopolis specimens. The ratio between phalanges III-2 and III-1 varies between 66% (Berlin), ~69% (Maxberg), 71% (Eichstatt), 79% (ninth), 81% (Solnhofen), 83% (11th), 86% (Munich) and 88% (Thermopolis). While this is quite a range, it is also gradational and seen in some other taxa (Struthiomimus, Dromiceiomimus).
The Eichstatt, Solnhofen, Berlin and possibly the 11th specimens have an unexpanded preacetabular processes, the London and probably the Munich and Thermopolis specimens have ventrally expanded processes. Senter and Robins (2003) suggested this could be due to ontogeny, but juvenile tyrannosaurids, Juravenator, Gallimimus, therizinosauroids, Microvenator, Bambiraptor and Scansoriopteryx all have expanded preacetabular processes, though the subadult Yangchuanosaurus shangyouensis holotype lacks one while the larger Y. magnus holotype has one. The preacetabular process varies in length between specimens, from 54% of pubic peduncle plus acetabulum length in the Solnhofen specimen to 89% (Eichstatt), ~111% (Munich), 120% (London), ~133% (11th) and 160% (Berlin). Elzanowski (2002) claimed the Berlin and Munich specimens lack an m. cuppedicus fossa on their ilia, unlike the London specimen, but such a fossa is clearly visible in the Berlin specimen (Ostrom, 1976- figure 20) while the Munich specimen seems to not preserve a lateral surface (Wellnhofer, 1993- plate 9). The Eichstatt specimen's ilium is only visible in medial view, while the Solnhofen specimen is too poorly preserved to tell. The London specimen differs from the Berlin, Eichstatt, Munich and Solnhofen specimens in having a dorsally concave ilium. The pubic angle of Archaeopteryx has been quite controversial, but is articulated at 3 degrees posterior to vertical in the Munich specimen. The pubis is disarticulated in the London, Berlin, Eichstatt, Solnhofen, Thermopolis and 11th specimens, so its angle cannot be used to distinguish species. The London and Thermopolis specimens have posterior pubic boots partially replaced by calcite (originally from cartilage?), while the Eichstatt, Munich, Berlin and 11th specimens seem to have more ossified pubic boots, but this could be ontogenetic. The London specimen differs from the Haarlem, Berlin and Eichstatt specimens (Ostrom, 1976) in having a transversely expanded pubic boot. The length of the pubic apron varies between 36% (Berlin), 39% (Solnhofen), 40% (Eichstatt), ~46% (London) and ~47% (Thermopolis), but may be overestimated in the last two due to their incompletely ossified distal ends. The obturator foramen identified by Petronievics in the London specimen is a pneumatic fossa (Christiansen and Bonde, 2000), and whether it is present in other specimens is uncertain due to a lack of posterior pubic exposure. The ischia of specimens differ a great deal, but this has not been recently and explicitly described. The London specimen has an obturator foramen (unique among maniraptoriforms), while a fossa is present in the Eichstatt and Munich specimen, and the Thermopolis and 11th specimens seemingly lack either. The proximoventral edge of the ischium is convex in the London specimen, unlike the Berlin, Eichstatt, Munich, Thermopolis and 11th specimens. The obturator process projects ventrally in the Munich and Thermopolis specimens, a bit less in the Eichstatt and 11th specimens, and not at all in the London specimen. The distodorsal process (at midlength) varies from a rounded bump in the London specimen and low angularity in the Munich specimen to a large triangular spine in the Solnhofen, 11th and especially Eichstatt specimens, to a large flange with a posterior notch in the Thermopolis specimen. Similarly, the proximodorsal process varies from a low peak (Berlin, Eichstatt, Thermopolis, 11th), to a slender point (Solnhofen), to a massive block-like process (Munich, London). The London specimen's further differs in having a notch proximally, making it rectangular. Ischial variation has not been examined much in other taxa, though Microraptor varies in the angle of the distal obturator process edge, obturator process expansion, shaft depth and ventral convexity proximal to the obturator process. Mirischia famously varies in the presence of an obturator process and notch. Tyrannosaurus varies in obturator process size and orientation, as well as proximodorsal process size, shaft curvature and distal expansion. The differences observed in Archaeopteryx specimens may be due to intraspecific variation as well.
Hindlimb ratios are explainable by allometry (Bennett, 2008), as are the more robust metatarsi of large specimens (Maxberg, Solnhofen) compared to smaller ones (Eichstatt, Munich, Thermopolis, 11th) (compare to juvenile tyrannosaurids vs. adults). Tibiotarsal and tarsometatarsal fusion is controversial in Archaeopteryx. It seems absent in the Eichstatt and Munich specimens. Tibiotarsal and metatarsal fusion are absent in the Thermopolis specimen, though the astragalus and calcaneum could be fused. In the Berlin and London specimens, there is no evidence for metatarsal fusion and at least the ascending process of the astragalus remains unfused to the tibia. Though Ostrom (1976) claimed the distal tarsal in the Maxberg specimen was "at least partially fused" to the metatarsus, he said the same of the Eichstatt specimen which seems to be untrue. Metatarsals II-IV of the Maxberg specimen are indistinguishable proximally and fused as determined by x-rays. The Solnhofen specimen lacks tibiotarsal and tarsometatarsal fusion, but metatarsals II-IV seem to be partially fused proximally. Fusion could be ontogenetic, of course, as the Solnhofen and Maxberg are among the largest specimens. The metatarsal II/IV ratio varies between 97% (Thermopolis), ~97% (Munich, Maxberg, 11th), 100% (Solnhofen), 104% (Eichstatt), and ~108% (Berlin). Tyrannosaurus has a similar variation (91-103%), and that of Dromiceiomimus is slightly less (90-97%). While Elzanowski (2001) emphasized the equal lengths in the Solnhofen specimen, it is intermediate between the other specimens and thus not an outlier. The proximally tapering second metatarsal in the right foot of the Solnhofen specimen is probably due to distortion as it is not present in the left foot. The phalanx II-2/II-1 ratio varies between 83% (Thermopolis), 85% (Berlin), 96-98% (11th), ~99% (Eichstatt), ~100% (Munich), 100% (London), 104% (Solnhofen) and ~105% (Maxberg), so would seem to distinguish the Berlin+Thermopolis specimens, as opposed to the Solnhofen specimen (contra Elzanowski, 2001). Ratios in Velociraptor are more variable (103-129%), showing this could be intraspecific variation. Pedal digit IV has four phalanges in the Solnhofen specimen (as in the Didactylornis type), but five phalanges in the Berlin, Eichstatt, Munich, Thermopolis and 11th specimens. This leads to the fourth digit being shorter in the Solnhofen specimen. Though the London specimen has an unknown number of phalanges in digit IV, it is long as in specimens with five phalanges. Pedal ungual IV is longer than phalanx IV-1 in the Solnhofen specimen, but not the Berlin, Eichstatt, Munich and Thermopolis specimens. Pedal ungual IV of the Solnhofen specimen is also distinct from the London, Berlin, Eichstatt, Munich, Thermopolis and 11th specimens in being straight ventrally. Variation in pedal ungual curvature has been reported in Deinonychus too (Ostrom, 1969). Pedal flexor tubercles are large in the London (I, II, III and IV) and Solnhofen (I and III but not IV) specimens, but small (though not absent) in the Berlin, Eichstatt, Munich, Thermopolis and 11th specimens. If Zhongornis is a juvenile Confuciusornis, it would provide an example of young specimens having smaller pedal flexor tubercles than adults.
When the characters above are entered into a matrix with Shenzhouraptor and Anchiornis as outgroups to establish polarity, the London+Munich specimens branch off first due to preacetabular length (also in the 11th), obturator area of ischium at least depressed (also in Eichstatt) and large proximodorsal ischial process. Other specimens are united with Shenzhouraptor by the low dorsal neural spines (not in the 11th specimen) and large distodorsal ischial process. The Berlin, Eichstatt, Thermopolis and 11th specimens are united by non-enlarged pedal flexor tubercles (also in Munich), while the Maxburg, Solnhofen and Shenzhouraptor are united by metatarsal fusion. The Solnhofen, ninth and Shenzhouraptor are united by a short manual phalanx I-1 (also in the Berlin specimen and some Anchiornis) and pedal ungual IV longer than IV-1 (also in some Anchiornis). The fact most of these characters are homoplasious shows that there is little evidence to subdivide the genus into species containing more than one individual, despite individual Archaeopteryx specimens (particularily the London and Solnhofen specimens) having several unique features. The choices are similar to that entertained for Microraptor on this site, either several species each represented by a single specimen, or one species which is variable in morphology. The latter more conservative approach is taken here, especially considering the fact no specimens are adult. Additional evidence is provided by the maniraptoromorph matrix of Hartman et al. 2019 where a topology of ((7(11(2,5)))(12((1,10)(6,8)))) is recovered, incompatable with any suggested distribution of taxa.
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Zhou, 2010. Comments on the proposed conservation of usage of Archaeopteryx lithographica von Meyer, 1861 (Aves) by designation of a neotype (Case 3390; see BZN 64: 182-184, 261-262; 65: 314-317; 66: 87-88, 357-358). Bulletin of Zoological Nomenclature. 67(1), 91-93.
Carney, Vinther, Shawkey, D'alba and Ackerman, 2011. Black feather color in Archaeopteryx. Journal of Vertebrate Paleontology. Program and Abstracts 2011, 84.
ICZN, 2011. OPINION 2283 (Case 3390) Archaeopteryx lithographica von Meyer, 1861 (Aves): Conservation of usage by designation of a neotype. Bulletin of Zoological Nomenclature. 68(3), 230-233.
Kawabe, Endo, Shimokawa, Miki and Matsuda, 2011. Allometric morphological changes in the avian brain. Journal of Vertebrate Paleontology. Program and Abstracts 2011, 134-135.
artdaily.cc, online 2011. An eleventh key witness for the theory of evolution by Charles Darwin becomes German Cultural Heritage.
Xu, You, Du and Han, 2011. An Archaeopteryx-like theropod from China and the origin of Avialae. Nature. 475, 465-470.
Carney, Vinther, Shawkey, D-Alba and Ackermann, 2012. New evidence on the colour and nature of the isolated Archaeopteryx feather. Nature Communications. 3:637.
Longrich, Vinther, Meng, Li and Russell, 2012. Primitive wing feather arrangement in Archaeopteryx lithographica and Anchiornis huxleyi. Current Biology. 22(23), 2262-2267.
Foth and Rauhut, 2013. A new look for an old bird: A new specimen of Archaeopteryx with exceptional feather preservation provides new insights into the evolution of feather plumages within Maniraptora. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 129.
Habib, 2013. Evidence against running takeoff in Archaeopteryx: Breaking the terrestrial vs. arboreal dichotomy. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 138.
Manning, Wogelius, Bergmann, Schwarz-Wings and Sellers, 2013. Synchronotron-based chemical imaging reveals plumage patterns in Archaeopteryx. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 171.
Manning, Edwards, Wogelius, Bergmann, Barden, Larson, Schwarz-Wings, Egerton, Sokaras, Mori and Sellers, 2013. Synchrotron-based chemical imaging reveals plumage patterns in a 150 million year old early bird. Journal of Analytical Atomic Spectrometry. 28, 1024-1030.
Carney, Molnar, Updike, Brown, Jackson, Shawkey, Lindgren, Sjovall, Falkingham and Gauthier, 2014. Archaeopteryx in 4D. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 103.
Egerton, Manning, Wogelius, Sellers, Schwarz-Wings, Sokaras, Mori, Edwards, Larson and Bergmann, 2014. Curatorial chemical secrets of Archaeopteryx. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 124.
Erickson, Rauhut, Roper, Loxchner and Norell, 2014. Long bone histology, growth, and the 'blood' of Archaeopteryx. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 126.
Foth, Tischlinger and Rauhut, 2014. New specimen of Archaeopteryx provides insights into the evolution of pennaceous feathers. Nature. 511, 79-82.
Habib, 2014. Reconstructing locomotor performance in Archaeopteryx. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 143.
Kundrat, Albersdoerfer, Nudds and Ahlberg, 2014. The Daiting specimen of Archaeopteryx. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 163.
Longrich, 2014. Primitive feather arrangement in Archaeopteryx lithographica sheds light on the origin and evolution of birds. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 170.
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Rauhut, 2014. New observations on the skull of Archaeopteryx. Paläontologische Zeitschrift. 88(2), 211-221.
Rauhut and Foth, 2014. New information on the theropod dinosaurs from the Late Jurassic lithographic limestones of Southern Germany. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 212.
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Schwarz-Wings and Kundrat, 2014. Postcranial skeletal pneumaticity in Archaeopteryx. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 225-226.
Wings, 2014. The digital Archaeopteryx - A high resolution photogrammetric 3D model benefiting future research. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 256.
Foth and Rauhut, 2015. Des Kaisers neue Kleider: Neues vom Urvogel Archaeopteryx. Jahresbericht 2014 und Mitteilungen. 43, 65-77.
Carney, 2016. Evolution of the archosaurian shoulder joint and the flight stroke of Archaeopteryx. Journal of Vertebrate Paleontology. Program and Abstracts, 110.
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Rauhut, Foth and Tischlinger, 2018. The oldest Archaeopteryx (Theropoda: Avialiae): A new specimen from the Kimmeridgian/Tithonian boundary of Schamhaupten, Bavaria. PeerJ. 6:e4191.
Voeten, Cubo, de Margerie, Roper, Beyrand, Bures, Tafforeau and Sanchez, 2018. Wing bone geometry reveals active flight in Archaeopteryx. Nature Communications. 9:923.
Carney, Tischlinger and Shawkey, 2019. Birds of a feather: Calamus corroborates identity of Archaeopteryx wing covert. Journal of Vertebrate Paleontology. Program and Abstracts 2019, 74.
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Schwarz, Kundrat, Tischlinger, Dyke and Carney, 2019. Ultraviolet light illuminates the avian nature of the Berlin Archaeopteryx skeleton. Scientific Reports. 9:6518.
Carney, Tischlinger and Shawkey, 2020. Evidence corroborates identity of isolated fossil feather as a wing covert of Archaeopteryx. Scientific Reports. 10:15593.

Ornithodesmiformes Martyniuk, 2012
Definition- (Ornithodesmus cluniculus, Dromaeosaurus albertensis, Troodon formosus <- Archaeopteryx lithographica) (Martyniuk, 2012)
Comments- This clade was named by Martyniuk (2012) presumedly based on the historical priority of Ornithodesmidae, and actually fulfills a useful role in the present topology assuming Ornithodesmus is an unenlagiid as recovered by Hartman et al.. However, it self destructs in the two alternate paravian topologies one step longer where Troodon is closer to Archaeopteryx than Dromaeosaurus. This and the uncertain position of Ornithodesmus makes such a clade unwise to use.
Reference- Martyniuk, 2012. A Field Guide to Mesozoic Birds and Other Winged Dinosaurs. Pan Aves. 189 pp.

unnamed ornithodesmiform (Jensen, 1981)
Late Kimmeridgian, Late Jurassic
Brushy Basin Member of the Morrison Formation, Colorado, US
Material- (BYUVP 2023) femur
Comments- This was first referred to Archaeopteryx by Jensen (1981), then to Theropoda indet. by Molnar (1985) and Maniraptora indet. by Jensen and Padian (1989). Hartman et al. (2019) included it in a phylogenetic analysis for the first time and recovered it as a deinonychosaur in the Unenlagiidae+Dromaeosauridae clade excluded from Halszkaraptorinae, Sinovenatorinae, Gobivenator+ other troodontids and Eudromaeosauria. It thus may belong to "Paleopteryx" or Hesperornithoides, but can only be compared to the latter in that both lack fourth trochanters.
References- Jensen, 1981. [A new oldest bird?] Anima (Tokyo). 1981, 33-39.
Jensen, 1981. Another look at Archaeopteryx as the worlds oldest bird. Encyclia, The Journal of the Utah Academy of Sciences, Arts, and Letters. 58, 109-128.
Molnar, 1985. Alternatives to Archaeopteryx; a survey of proposed early or ancestral birds. In Hecht, Ostrom, Viohl and Wellnhofer (eds.). The Beginnings of Birds. Freunde des Jura-Museums Eichstatt. 209-217.
Jensen and Padian, 1989. Small pterosaurs and dinosaurs from the Uncomphagre fauna (Brushy Basin Member, Morrison Formation: ?Tithonian), Late Jurassic, western Colorado. Journal of Paleontology. 63(3), 364-373.
Padian, 1998. Pterosaurians and ?avians from the Morrison Formation (Upper Jurassic, western U.S.). Modern Geology. 23, 57-68.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

unnamed ornithodesmiform (Rodriguez de la Rosa and Cevallos-Ferriz, 1998)
Early Maastrichtian, Late Cretaceous
Cañon del Tule Formation, Mexico
Material- (IGM-7715) distal pedal phalanx II-2
Comments- Although described as being from the Cerro del Pueblo Formation, Aguillon Martinez (2010) found this and other material from the El Pelillal locality belong to the later Cañon del Tule Formation.
This was tentatively referred to Dromaeosauridae by Rodriguez de la Rosa and Cevallos-Ferriz (1998) based on the dorsally placed collateral ligament pit. However, this character is also present in basal troodontids (e.g. IGM 100/44, Sinornithoides, Borogovia), Neuquenraptor and Rahonavis. It is a different taxon than IGM-7710 and IGM-7712, both of which have centrally placed collateral ligement pits.
References- Rodriguez de la Rosa and Cevallos-Ferriz, 1998. Vertebrates of the El Pelillal locality (Campanian, Cerro del Pueblo Formation), southeastern Coahuila, Mexico. Journal of Vertebrate Paleontology. 18(4), 751-764.
Aguillon Martinez, 2010. Fossil vertebrates from the Cerro del Pueblo Formation, Coahuila, Mexico, and the distribution of Late Campanian (Cretaceous) terrestrial vertebrate faunas. MS thesis, Dedman College Southern Methodist University. 135 pp.

Migmanychion Wang, Cau, Wang, Yu, Wu, Wang and Liu, 2023 online
M. laiyang Wang, Cau, Wang, Yu, Wu, Wang and Liu, 2023 online
Early Aptian, Early Cretaceous
Pigeon Hill, Longjiang Formation, Inner Mongolia, China
Holotype- (LY 2022JZ3001) dorsal rib fragments, distal radius, distal ulna, distal carpal I, metacarpal I (23.1 mm), phalanx I-1 (41.8 mm), manual ungual I (28.6 mm), metacarpal II (52.8 mm), phalanx II-1 (31.6 mm), phalanx II-2 (43.7 mm), manual ungual II (35.8 mm), metacarpal III (52.7 mm), phalanx III-1 (15.1 mm), phalanx III-2 (15.0 mm), phalanx III-3 (24.9 mm), manual ungual III (18.5 mm)
Diagnosis- (after Wang et al., 2023) differs from other taxa except Fukuivenator in- discoidal distal carpal 1 capping exclusively metacarpal I (unknown in Fukuivenator); sharp proximolateral flange on the ventral surface of metacarpal I; manual phalanx II-1 with lateroventral ridge (also in some paravians); manual ungual II dorsoventrally shallower but proximodistally longer than manual ungual I; manual unguals I and III having a prominent proximodorsal lip and the dorsal margin arched well above the level of the articular facet when the latter is oriented vertically.
differs from Fukuivenator in- metacarpal I more than four times longer than distally wide and narrower than metacarpal II; metacarpal III being no more than 40% of metacarpal II width at mid-shaft (55% in Fukuivenator); flexor tubercle manual ungual I distally displaced relative to proximal articular facet; manual ungual II with dorsal margin arched well above the level of the articular facet when the latter is oriented vertically; manual ungual III half the size of manual ungual II (in Fukuivenator ungual III is >80% the size of ungual II).
Comments- This was discovered in 2022. Wang et al. (2023) used Cau's meagmatrix to recover Migmanychion sister to Fukuivenator, which is in turn sister to Pennaraptora. Two steps were needed to force it to be sister to Pennaraptora (which left Fukuivenator more basal), and three steps were needed to make it a therizinosaur (where it remains sister to Fukuivenator), oviraptorosaur or within Eumaniraptora (as either an archaeopterygid or dromaeosaurid). In Hartman et al.'s maniraptoromorph matrix, Migmanychion resolves as a paravian either sister to other dromaeosaurids or anywhere in Halszkaraptorinae. One step can make it an archaeopterygid or unenlagiine, while two steps can make it a troodontid, basalmost deinonychosaur, basalmost avialan, basalmost oviraptorosaur, sister to Pennaraptora, sister to Therizinosauria+Alvarezsauroidea, basalmost maniraptoran, basalmost ornithomimosaur, sister to Maniraptoriformes or sister to Ornitholestiinae (which includes Fukuivenator, although making it sister to that genus takes three steps). Thus its fragmentary preservation and unspecialized morphology make Migmanychion plausibly fit many places between ornitholestiids and Euavialae, although generally not within the known content of each subclade. Notably the basal deinonychosaur position preferred here makes referral of additional Pigeon Hill specimens LY 2022JZ3004 (pelvic area referred to Paraves by Wang et al.) and LY 2022JZ3005 (subarctometatarsal metatarsi with distally placed halluces referred to Coelurosauria by Wang et al.) plausible.
Reference- Wang, Cau, Wang, Yu, Wu, Wang and Liu, 2023 online. A new theropod dinosaur from the Lower Cretaceous Longjiang Formation of Inner Mongolia (China). Cretaceous Research. Journal Pre-proof, 10565. DOI: 10.1016/j.cretres.2023.105605.

Ornithodesmidae Hooley, 1913
Definition- (Ornithodesmus cluniculus <- Archaeopteryx lithographica, Passer domesticus, Paronychodon lacustris, Pterodactylus antiquus) (Martyniuk, 2012)
References- Hooley, 1913. On the skeleton of Ornithodesmus latidens; an ornithosaur from the Wealden Shales of Athersfield (Isle of Wight). Quarterly Journal of the Geological Society. 69, 372-421.
Martyniuk, 2012. A Field Guide to Mesozoic Birds and Other Winged Dinosaurs. Pan Aves. 189 pp.
Ornithodesmus Seeley, 1887
O. cluniculus Seeley, 1887
Barremian, Early Cretaceous
Wessex Formation, England
Holotype- (NHMUK R187) (sacrum- 96 mm) first sacral vertebra (17 mm), second sacral vertebra (16 mm), third sacral vertebra (18 mm), fourth sacral vertebra (15 mm), fifth sacral vertebra (16 mm), sixth sacral vertebra (13 mm)
Comments- The holotype was purchased from the Fox collection in 1884 (Lydekker, 1888). Seeley (1887) originally described Ornithodesmus as a bird, but Hulke (in Anonymous, 1887) soon suggested it was pterosaurian. Seeley later (1901) referred pterosaur skeleton NHMUK R176 to Ornithodesmus as a new species, O. latidens. For over a century, the well known pterosaur Ornithodesmus latidens was used as the standard example of the genus. This ended in 1993 when Howse and Milner reidentified the Ornithodesmus cluniculus holotype as a theropod (the pterosaur was later renamed Istiodactylus latidens by Howse et al., 2001). Specifically they believed it to be a troodontid, based largely on comparison to NHMUK R4463 (another supposed troodontid sacrum). Makovicky (1995) and Norell and Makovicky (1997) identified NHMUK R4463 as Saurornitholestes, and the latter reference noted Ornithodesmus resembles Dromaeosauridae in possessing a well developed dorsal ridge formed by zygapophyses. Makovicky stated the specimen was "probably neither a troodontid nor a dromaeosaurid" while Naish et al. (2001) stated some characters argue against a dromaeosaurid identity, such as transverse processes which are not dorsoventrally flattened. That character is meaningless outside of a phylogenetic context however. As an alternative, Naish et al. note resemblence to Coelophysis rhodesiensis and Carnotaurus in the presence of six sacrals, neural spine lamina and neural platform. Yet coelophysoids never have more than five sacrals, and dromaeosaurids like Velociraptor have all three listed characters. In addition, no coelophysoids or ceratosaurs have sacral pleurocoels or flattened ventral sacral surfaces with a median groove, unlike Ornithodesmus and dromaeosaurids. It was first included in the maniraptoromorph analysis of Hartman et al. (2019) who recovered it in Unenlagiinae, but after the addition of more data it can also fall out in Halszkaraptorinae or as a basal dromaeosaurid with an equal number of steps.
References- Seeley, 1887. On a sacrum, apparently indicating a new type of bird, Ornithodesmus cluniculus, Seeley, from the Wealden of Brook. Quarterly Journal of the Geological Society of London. 42, 206-211.
Anonymous, 1887. Discussion (on Ornithodesmus and Patricosaurus). Quarterly Journal of the Geological Society of London. 43, 219-220.
Lydekker, 1888. Catalogue of the Fossil Reptilia and Amphibia in the British Museum (Natural History), Cromwell Road, S.W., Part 1. Containing the Orders Ornithosauria, Crocodilia, Dinosauria, Squamata, Rhynchocephalia, and Proterosauria. British Museum of Natural History. 309 pp.
Seeley, 1901. Dragons of the Air. Methuen & Co.. 239 pp.
Howse and Milner, 1993. Ornithodesmus - a maniraptoran theropod dinosaur from the Lower Cretaceous of the Isle of Wight, England. Palaeontology. 36, 425-437.
Makovicky, 1995. Phylogenetic aspects of the vertebral morphology of Coelurosauria (Dinosauria: Theropoda). Masters Thesis, University of Copenhagen. 311 pp.
Norell and Makovicky, 1997. Important features of the dromaeosaur skeleton: Information from a new specimen. American Museum Novitates. 3215, 28 pp.
Howse, Milner and Martill, 2001. Pterosaurs. In Martill and Naish (eds.). Dinosaurs of the Isle of Wight. The Palaeontological Association. 324-335.
Naish, Hutt and Martill, 2001. Saurischia dinosaurs: Theropods. In Martill and Naish (eds). Dinosaurs of the Isle of Wight. The Palaeontological Association. 242-309.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Pyroraptor Allain and Taquet, 2000
P. olympius Allain and Taquet, 2000
Late Campanian-Early Maastrictian, Late Cretaceous
La Boucharde, Bouches-du-Rhone, France
Holotype- (MNHN BO001) pedal ungual II (66 mm)
Paratypes- (MNHN BO002) pedal phalanx II-2 (23 mm)
(MNHN BO003) metatarsal II (118.7 mm)
(MNHN BO004) pedal ungual II
(MNHN BO005) ulna (112.8 mm)
(MNHN BO014) tooth
(MNHN BO015) tooth
Referred- (MNHN BO006-BO010) pedal phalanges including II-2 (~28 mm) (Allain and Taquet, 2000)
(MNHN BO011) manual phalanx (Allain and Taquet, 2000)
(MNHN BO012) metatarsal I (Allain and Taquet, 2000)
(MNHN BO013) incomplete radius (Allain and Taquet, 2000)
(MNHN BO016) proximal caudal vertebra (24 mm) (Allain and Taquet, 2000)
(MNHN BO017) dorsal vertebra (Allain and Taquet, 2000)
(MNHN coll.) distal metatarsal III (Turner, Makovicky and Norell, 2012)
Late Campanian-Early Maastrichtian, Late Cretaceous
Montrebei, Tremp Formation, Spain
(DPM-MON-T1) tooth (6.3x3.3x2.4 mm) (Torices, Currie, Canudo and Pereda-Suberbiola, 2015)
Late Campanian, Late Cretaceous
Laño, Sedano Formation, Spain
(MCNA 14623) dentary fragment, tooth (8x5.4x2.4 mm) (Torices, Currie, Canudo and Pereda-Suberbiola, 2015)
(MCNA 14624) dentary fragment, tooth (6.2x4.3x1.9 mm) (Torices, Currie, Canudo and Pereda-Suberbiola, 2015)
(MCNA 14625) tooth (3.9x3.1x1.4 mm) (Torices, Currie, Canudo and Pereda-Suberbiola, 2015)
(MCNA 14626) tooth (3.8x2.5x1.4 mm) (Torices, Currie, Canudo and Pereda-Suberbiola, 2015)
Diagnosis- (after Allain and Taquet, 2000) ventrally concave metatarsal II.
Other diagnoses- Turner et al. (2012) noted the supposed deep m. brachialis fossa on the ulna is due to crushing. The other characters listed in Allain and Taquet's (2000) diagnosis are common in dromaeosaurids- teeth distally serrated and with restricted mesial serrations; ulna subequal in lenth to metatarsus; asymmetrically ginglymoid metatarsal II; strongly curved pedal ungual II.
Comments- The hypodigm was discovered from 1993-1998. At least two individuals are present in the type material, based on a larger second pedal phalanx II-2 (Turner et al., 2012). Turner et al. also noted a metatarsal III is present in the collection, and Allain and Taquet misidentified metatarsal I as a distal metacarpal I. DPM-MON-T1 was first described as Dromaeosauridae indet. 3 by Torices (2002). Torices et al. (2015) identified several teeth and dentary fragments based on morphometric analysis, plus spatiotemporal similarity.
Pyroraptor may be a junior synonym of the contemporary dromaeosaurid Variraptor, but this cannot be established until the dorsal vertebra MNHN BO017 or additional specimens are described. Alternatively, the paratypes and referred specimens of Variraptor may belong to Pyroraptor instead. They are not comparable presently.
Senter et al. (2004) included Pyroraptor in their phylogenetic analysis of coelurosaurs and found it to be a dromaeosaurid excluded from Microraptoria (based on the stout pedal phalanx II-2) and Dromaeosaurus+Utahraptor (based on the high DSDI). Turner et al. found it to fall within Dromaeosauridae, but outside Eudromaeosauria (including Bambiraptor in their trees). Hartman et al. (2019) recovered it as an unenlagiine, but with the addition of more data it can equally parsimoniously be a microraptorian dromaeosaurid.
References- Allain and Taquet, 2000. A new genus of Dromaeosauridae (Dinosauria, Theropoda) from the Upper Cretaceous of France. Journal of Vertebrate Paleontology. 20(2), 404-407.
Torices, 2002. Los dinosaurios terópodos del Cretácico Superior de la Cuenca de Tremp (Pirineos Sur-Centrales, Lleida). Coloquios de Paleontología. 53, 139-146.
Senter, Barsbold, Britt and Burnham, 2004. Systematics and evolution of Dromaeosauridae. Bulletin of Gunma Museum of Natural History. 8, 1-20.
Turner, Makovicky and Norell, 2012. A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American Museum of Natural History. 371, 206 pp.
Torices, Currie, Canudo and Pereda-Suberbiola, 2015. Theropod dinosaurs from the Upper Cretaceous of the South Pyrenees basin of Spain. Acta Palaeontologica Polonica. 60(3), 611-626.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Yaverlandia Galton, 1971
Y. bitholus Galton, 1971
Barremian, Early Cretaceous
Wessex Formation, England
Holotype- (MIWG 1530) frontals, orbitosphenoid fragment
Diagnosis- (after Galton, 1971) frontals thickened with two domes; frontals with pitted surface.
(proposed) fused frontals.
Other diagnoses- Galton (1971) also included frontal-orbit contact and the unrestricted supratemporal fenestrae as diagnostic within Pachycephalosauria, but these are typical of theropods.
Comments- This specimen was found in 1923 and originally considered to perhaps be referrable to Vectisaurus (Watson, 1930; Swinton, 1936), though Watson also noted resemblence to Stegoceras (his Troodon). Galton (1971) named the taxon Yaverlandia bitholus, and assigned it to the Pachycephalosauridae, which was followed by most authors until recently. When entered into cladistic analyses of Pachycephalosauria, Yaverlandia was resolved at the base of the clade (Williamson and Carr, 2002) or as a basal pachycephalosaurid (Sereno, 2000). However, Hopson (1979) and Giffin (1989) doubted a pachycephalosaurian identity, based on the structure of the endocranium. Sullivan (2000, 2003) noted several characters incongruent with a pachycephalosaurian identity- frontals with broad orbital contact; parietals excluded from domes; supratemporal fenestrae contact frontals. Naish (2004) determined Yaverlandia is not a pachycephalosaur, though its identity remained elusive in his abstract. Naish (2006) noted the taxon shares a few characters with pachycephalosaurids but lacks pachycephalosaurian and marginocephalian characters, suggesting either significant reversals or convergence. He classified the genus as a maniraptoriform based on ventrally extending, laterally concave ridges that form the lateral margins of the cerebral concavity and ventrally concave dorsal orbital margins, and furthermore as a troodontid. Yet most of the troodontid-like characters are also present in unenlagiines and Halszkaraptor, neither considered by Naish, so Yaverlandia is here assigned to Ornithodesmiformes instead.
References- Watson, 1930. Proceedings of the Isle of Wight Natural History Society. 2, 60.
Swinton, 1936. The dinosaurs of the Isle of Wight. Proceedings of the Geologists' Association. 47, 204-220.
Galton, 1971. A primitive dome-headed dinosaur (Ornithischia; Pachycephalosauridae) from the Lower Cretaceous of England and the function of the dome of pachycephalosaurids. Journal of Paleontology. 45(1), 40-47.
Hopson, 1979. Paleoneurology. In Gans, Northcutt and Ulinski (eds.). Biology of the Reptilia (Neurology A). Academic Press. 9, 39-146.
Wall and Galton, 1979. Notes on pachycephalosaurid dinosaurs (Reptilia: Ornithischia) from North America, with comments on their status as ornithopods. Canadian Journal of Earth Sciences. 16(6), 1176-1186.
Giffin, 1989. Pachycephalosaur paleoneurology (Archosauria: Ornithischia). Journal of Vertebrate Paleontology. 9(1), 67-77.
Sereno, 2000. The fossil record, systematics and evolution of pachycephalosaurs and ceratopsians from Asia. In Benton, Shishkin, Unwin and Kurochkin (eds.). The Age of Dinosaurs in Russia and Mongolia. Cambridge University Press. 480-516.
Sullivan, 2000. Prenocephale edmontonensis (Brown and Schlaikjer) new comb. and P. brevis (Lambe) new comb. (Dinosauria: Ornithischia: Pachycephalosauria) from the Upper Cretaceous of North America. New Mexico Museum of Natural History and Science Bulletin. 17, 177-190.
Naish and Martill, 2001. Boneheaded and horned dinosaurs. In Martill and Naish (eds.). Dinosaurs of the Isle of Wight. The Palaeontological Association, London. 133-146.
Williamson and Carr, 2002. A new genus of derived pachycephalosaurian from western North America. Journal of Vertebrate Paleontology. 22(4), 779-801.
Sullivan, 2003. Revision of the dinosaur Stegoceras Lambe (Ornithischia, Pachycephalosauridae). Journal of Vertebrate Paleontology. 23(1), 181-207.
Naish, 2004. So... what is Yaverlandia? SVPCA 2004 Abstracts. [pp]
Naish, 2006. The osteology and affinities of Eotyrannus lengi and Lower Cretaceous theropod dinosaurs from England. PhD thesis, University of Portsmouth. 353 pp.
Sullivan, 2006. A taxonomic review of the Pachycephalosauridae (Dinosauria: Ornithischia). New Mexico Museum of Natural History and Science Bulletin. 35, 347-365.
Naish, 2011. Theropod dinosaurs. In Batten (ed.). English Wealden Fossils. The Palaeontological Association. 526-559.

Unenlagiidae

Deinonychosauria sensu Sereno, 1997
Definition- (Troodon formosus + Dromaeosaurus albertensis) (modified)
= Deinonychosauria sensu Sereno, 1998
Definition- (Troodon formosus + Velociraptor mongoliensis) (modified)

undescribed deinonychosaur (Fortner, 2015)
Early Maastrichtian, Late Cretaceous
Aguja Formation, Texas, US
Material- partial postcranial skeleton
Comments- This was said to be "compatible with identification as either Troodontidae or Dromaeosauridae." It may be Richardoestesia or Paronychodon, if not a eudromaeosaur or troodontine.
Reference- Fortner, 2015. A small theropod dinosaur from the Aguja Formation (Upper Cretaceous), Big Bend National Park, Texas. Journal of Vertebrate Paleontology. Program and Abstracts 2015, 126.

Dromaeosauridae

Troodontidae Gilmore, 1924
Definition- (Troodon formosus <- Ornithomimus velox, Mononykus olecranus, Therizinosaurus cheloniformes, Oviraptor philoceratops, Archaeopteryx lithographica, Unenlagia comahuensis, Velociraptor mongoliensis, Passer domesticus) (Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019)
Other definitions- (Troodon formosus, Saurornithoides mongoliensis, Borogovia gracilicrus, Sinornithoides youngi <- Ornithomimus velox, Oviraptor philoceratops) (Varricchio, 1997)
(Troodon formosus <- Velociraptor mongoliensis) (Makovicky and Norell, 2004; modified from Sereno, 1998)
(Troodon formosus <- Ornithomimus velox, Mononykus olecranus, Therizinosaurus cheloniformes, Oviraptor philoceratops, Velociraptor mongoliensis, Passer domesticus) (modified from Senter, Barsbold, Britt and Burnham, 2004)
(Troodon formosus <- Ornithomimus edmontonicus, Velociraptor mongoliensis, Passer domesticus) (Sereno, online 2005)
(Troodon formosus <- Deinonychus antirrhopus, Passer domesticus) (Hu, Hou, Zhang and Xu, 2009)
(Troodon formosus <- Velociraptor mongoliensis, Passer domesticus) (Turner, Makovicky and Norell, 2012)
(Troodon formosus <- Dromaeosaurus albertensis, Passer domesticus) (Godefroit, Cau, Hu, Escuillié, Wu and Dyke, 2013)
= Saurornithoididae Barsbold, 1974
= Troodontidae sensu Sereno, 1998
Definition- (Troodon formosus <- Velociraptor mongoliensis) (modified)
= Troodontidae sensu Sereno, online 2005
Definition- (Troodon formosus <- Ornithomimus edmontonicus, Velociraptor mongoliensis, Passer domesticus)
= Troodontoidea Gilmore, 1924 vide Livezey and Zusi, 2007
= Troodontidae sensu Hu, Hou, Zhang and Xu, 2009
Definition- (Troodon formosus <- Deinonychus antirrhopus, Passer domesticus)
= Troodontia Alifanov, 2012
= Troodontidae sensu Turner, Makovicky and Norell, 2012
Definition- (Troodon formosus <- Velociraptor mongoliensis, Passer domesticus)
= Troodontidae sensu Godefroit, Cau, Hu, Escuillié, Wu and Dyke, 2013
Definition- (Troodon formosus <- Dromaeosaurus albertensis, Passer domesticus)
Comments- The first troodontids discovered were assigned to the Megalosauridae (Saurornithoides in Osborn, 1924) and Coeluridae (Stenonychosaurus in Sternberg 1932), both waste-basket families at the time. Troodontidae was proposed for pachycephalosaurs by Gilmore (1924) who believed Troodon to be a Stegoceras tooth, until Sternberg (1945) named Pachycephalosauridae and moved Troodon back to Theropoda. Barsbold's (1974) Saurornithoididae was used for a time until Currie (1987) synonymized Stenonychosaurus with Troodon, with Troodontidae being used ever since.
Two main alternatives have been proposed for the placement of troodontids within Theropoda, with Ostrom (1969), Barsbold (1976) and Gauthier (1984) combining them with dromaeosaurids in Deinonychosauria based largely on the shared hyperextendable and enlarged pedal ungual II, while Thulborn (1984), Currie (1985), Bakker (1986) and Holtz (1992) placed them closer to ornithomimids in Bullatosauria based largely on the shared inflated parasphenoid cultriform process. While this was controversial throughout the 1990s, the description of basal bird-like Sinovenator in 2002 cemented maniraptoran and paravian troodontids, with Senter et al. (2004) probably the last quantitative analysis to support Bullatosauria (and only because Sinovenator as drawn away from other troodontids into Dromaeosauridae).
Troodontidae defined- Sereno's newest (online 2005) definition differs from his earlier (1998) one which only had Velociraptor as an external specifier, and Senter et al.'s (2004), which had Mononykus, Therizinosaurus and Oviraptor as additional external specifiers. Keeping Oviraptor seems useful, in the case Osmólska and Barsbold (1990), Russell and Dong (1994) or Norell et al. (2001) are correct. I'm not aware of any topology placing Shuvuuia or Therizinosaurus closer to Troodon than the other taxa, but they both seem relatively plausible as troodontid sister taxa. Hartman et al. (2019) found topologies pairing troodontids with archaeopterygids were only a single step longer than grouping troodontids with dromaeosaurids, so added Archaeopteryx as an external specifier so that Archaeopterygidae could not be a senior synonym of Troodontidae.
Troodontoidea- Livezey and Zusi (2007) in commentary for their large avian analysis list cite "Troodontoidea (Troodon and Saurornithoides)", which while possibly a typo (as no other troodontid OTUs were used) is also among many higher-level taxa stated as new that are used in this work (e.g. Palaeoaves, Rahoinaviformes, Rahonavidae, Apsaraviformes, Apsaravidae...). Bhullar et al. (2012) use Troodontoidea in their cladogram without comment.
Microtroodontidae- Wiemann et al. (2018) use the term microtroodontid without elaboration, first stating "Egg colour pigments are preserved in eggshells from the oviraptorid Heyuannia huangi, Mongolian microtroodontids..." and indicating in Supplementary Table 2 that the two specimens considered microtroodontids are IGM 100/1323 (later made the holotype of Almas) and MAE 14-20, which has never been mentioned outside of Wiemann's eggshell dataset but is stated to also be from the Djadochkta Formation. Shown as a clade exclusive of other troodontids (a Two Medicine Troodon egg, two Djadokhta eggs and PFMM-0014003517 from the Chichengshan Formation and also not mentioned outside Wiemann's datasets), this is said to be "a composite topology (supertree) from previously published phylogenies" 8, 31 and 32, but none of the three references include MAE 14-20. The term "microtroodontid" is later used in Norell et al. (2020; supplementary info) and Jiang et al. (2023), but with no further elaboration. According to ICZN Article 11.7.11 a family-group name must be "formed from the stem of an available generic name" which "must be a name then used as valid in the new family-group taxon." As Wiemann et al. did not intend for a genus 'Microtroodon' to be a microtroodontid, it is invalid. It also fails ICZN Article 13.1.1 ("be accompanied by a description or definition that states in words characters that are purported to differentiate the taxon"), 16.1 ("Every new name published after 1999, including new replacement names (nomina nova), must be explicitly indicated as intentionally new") and 16.2 (" a new family-group name published after 1999 must be accompanied by citation of the name of the type genus (i.e. the name from which the family-group name is formed)").
Macrotroodontidae- Wiemann et al. (2018) also use the term macrotroodontid without explanation, stating "Both egg colour pigments were detected in eggshells from H. huangi, the Mongolian microtroodontid (IGM 100/1323) and macrotroodontid (AMNH FARB 6631)", which seems to be what they call "Large Troodontid" in Supplementary Table 2 and includes Two Medicine Troodon egg YPM PU 23259, two Djadokhta eggs (AMNH 6631 and IGM 100/1003; perhaps Saurornithoides, Gobivenator and/or Byronosaurus) and PFMM-0014003517 from the Chichengshan Formation. Unlike 'microtroodontid', the term was not used in subsequent papers, but it is invalid due to the same ICZN Articles (11.7.11, 13.1.1, 16.1 and 16.2).
No longer troodontids- Note that in cases where specimens consist only of teeth, these are only referred to Troodontidae here if they match those morphologies found with known troodontid skulls (roots constricted and carinae either unserrated, serrated only distally, or with large serrations present on both carinae). Teeth with both carinae finely serrated are known in Hesperornithoides, but this early taxon can easily move to other positions within Paraves (Dromaeosauridae, Archaeopterygidae, basal Avialae). Thus many teeth with finely serrated mesial and distal carinae and constricted bases are reassigned to Paraves here, often resembling some Microraptor teeth most, but probably members of poorly known paravian clades in most cases considering their temporal and geographic position. That being said, some posterior teeth of Microraptor and Caihong would also fall under the serrated troodontid morphospace, so some teeth listed as troodontids below may end up being e.g. dromaeosaurids or archaeopterygids.
Currie et al. (1990) said that troodontid teeth reported from the Cedar Mountain Formation by Nelson and Crooks (1987) were more likely velociraptorines because of the serrations are small (12/mm) and elongate.
Supposed troodontid teeth from the Mussentuchit Member of the Cedar Mountain Formation first noted by Parrish and Eaton (1991) and described by Frederickson et al. (2018) are here identified as microraptorian instead.
Bertini and Franco-Rosas (2001) state "Troodontidae teeth were recognized" among over 200 specimens from the Late Cretaceous Adamantina and Marilia Formations of the Bauru Group in Brazil, probably originating with Bertini's (1993) and Franco's (1999) theses. In publications which describe supposedly troodontid-like teeth from these formations, they are not distinguishable from e.g. noasaurids which are more geographically plausible. Thus they are referred to Averostra here.
Eaton (1999) reported troodontid teeth from the Iron Springs Formation of Utah, but these were not present in the final report of Eaton et al. (2014) and may have been based on dromaeosaurid tooth UMNH VP 24114 or Theropod indet. tooth UMNH VP 24116.
Kirkland et al. (1998) listed Troodontidae indet. from the basal Straight Cliffs Formation and the Straight Cliffs Formation, while Eaton et al. (1999) lists Troodontidae indet. from the Smoky Hollow Member (but not the John Henry Member) of the Straight Cliffs Formation. However, Parrish (1999) doesn't record any troodontid specimens from either member in his study, suggesting they were misidentified.
Although Metcalf and Walker (1994) identified a tooth from the Bathonian Chipping Norton Formation of England as a possible troodontid, it is more likely a dromaeosaurid.
Nessov (1995) cited a troodontid astragalocalcaneum from the Bostobe Formation of Kazakhstan, but Averianov and Sues (2007) noted many other maniraptorans have fused astragalocalcanea as well. Kordokova et al. (1996) cited troodontids from the Zhirkindek and Bostobe Formations of Kazakhstan, but these were not mentioned in their later (2001) paper. Averianov (2007) could not confirm the presence of troodontids from either formation, but described a frontal as Troodontidae indet. in 2016..
Nessov (1995) identified CCMGE 484/12457 as a troodontid frontal, which he named Saurornithoides isfarensis. Though they could not locate it, Averianov and Sues (2007) reidentified the specimen as a hadrosaurid prefrontal.
Dong (1997) described tooth IVPP V11122-2 from the Zhonggou Formation of China as Troodontidae, but it is here placed in Deinonychosauria.
Csiki and Grigorescu (1998) described five teeth from the Hateg Formation of Romania (FGGUB R.1318, R.1319, R.1320 and MAFI v.12685a and b) as "troodontid-like", more precisely "probably more closely related to troodontids (?and "paronychodons") than to other small theropods." However these more closely resemble the then-unknown Microraptor and are here assigned to Deinonychosauria.
Codrea et al. (2002) described teeth as troodontid-like from the Sinpetru Beds of Romania (IRSNB coll.), but these are referred here to Averostra.
Debeljak et al. (2002) described a tooth from the Late Cretaceous of Slovenia (ACKK-D-8/088) as ?troodontid, but it is here referred to Deinonychosauria.
Codrea et al. (2012) described tooth UBB NgTh1 from the Rusca Mountain Basin of Romania as being troodontid-like, but it is here placed as ?Averostra.
Ford (online 2015) placed tooth B of Huene (1934; CA coll.) in Troodontidae without rationale, but it is a narrow D-shape unlike members of that clade and is placed as Averostra indet. here following Soto and Cambiaso (2006).
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Osborn, 1924. Three new Theropoda, Protoceratops zone, central Mongolia. American Museum Novitates. 144, 1-12.
Sternberg, 1932. Two new theropod dinosaurs from the Belly River Formation of Alberta. Canadian Field-Naturalist. 46(5), 99-105.
Huene, 1934. Neue Saurier-Zähne aus der Kreide von Uruguay. Centralblatt für Mineralogie, Geologie und Paläontologie, Abteilung B: Geologie und Paläontologie. 1934(4),183-189.
Sternberg, 1945. Pachycephalosauridae proposed for domeheaded dinosaurs, Stegoceras lambei n. sp., described. Journal of Paleontology. 19, 534-538.
Ostrom, 1969. Osteology of Deinonychus antirrhopus, an unusual theropod from the Lower Cretaceous of Montana. Peabody Museum of Natural History Bulletin. 30, 1-165.
Barsbold, 1974. Saurornithoididae, a new family of small theropod dinosaurs from central Asia and North America. Palaeontologia Polonica. 30, 5-22.
Barsbold, 1976. K evolyutsii i sistematike pozdnemezozoyskikh khishchnykh dinozavrov. In Kramarenko, Luvsandansan, Voronin, Barsbold, Rozhdestvensky, Trofimov and Reshetov (eds.). Paleontology and Biostratigraphy of Mongolia. The Joint Soviet-Mongolian Paleontological Expedition, Transactions. 3, 68-75.
Gauthier, 1984. A cladistic analysis of the higher systematic categories of the Diapsida. PhD thesis. University of California, Berkeley. 564 pp.
Thulborn, 1984. The avian relationships of Archaeopteryx, and the origin of birds. Zoological Journal of the Linnean Society. 82(1-2), 119-158.
Currie, 1985. Cranial anatomy of Stenonychosaurus inequalis (Saurischia, Theropoda) and its bearing on the origin of birds. Canadian Journal of Earth Sciences. 22(1), 643-658.
Bakker, 1986. The Dinosaur Heresies. Kensington, New York. 481 pp.
Currie, 1987. Bird-like characteristics of the jaws and teeth of troodontid theropods (Dinosauria, Saurischia). Journal of Vertebrate Paleontology. 7, 72-81.
Nelson and Crooks, 1987. Stratigraphy and paleontology of the Cedar Mountain Formation (Lower Cretaceous), eastern Emery County, Utah. In Averett (ed.). Paleontology and Geology of the Dinosaur Triangle: Guidebook for 1987 Field Trip. Museum of western Colorado, Grand Junction. 55-63.
Currie, Rigby and Sloan, 1990. Theropod teeth from the Judith River Formation of southern Alberta, Canada. In Carpenter and Currie (eds.). Dinosaur Systematics: Perspectives and Approaches. Cambridge University Press. 107-125.
Osmólska and Barsbold, 1990. Troodontidae. In Weishampel, Dodson, and Osmólska (eds.). The Dinosauria. University of California Press. 259-268.
Parrish and Eaton, 1991. Diversity and evolution of dinosaurs in the Cretaceous of the Kaipirowits plateau, Utah. Journal of Vertebrate Paleontology. 11(3), 50A.
Holtz, 1992. An unusual structure of the metatarsus of Theropoda (Archosauria: Dinosauria: Saurischia) of the Cretaceous. PhD thesis. Yale University. 347 pp.
Bertini, 1993. Paleobiologia do Grupo Bauru, Cretáceo Superior continental da Bacia do Paraná, com ênfase em sua fauna de amniotas. PhD thesis, Universidade Federal do Rio de Janeiro. 493 pp.
Metcalf and Walker, 1994. A new Bathonian microvertebrate locality in the English midlands. In Fraser and Sues (eds.). In the Shadow of the Dinosaurs - Mesozoic Small Tetrapods. Cambridge University Press. 322-332.
Russell and Dong, 1994. The affinities of a new theropod from the Alxa Desert, Inner Mongolia, People’s Republic of China. Canadian Journal of Earth Sciences. 30(10), 2107-2127.
Nessov, 1995. Dinosaurs of nothern Eurasia: New data about assemblages, ecology, and paleobiogeography. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University, St. Petersburg. 1-156.
Kordikova, Gunnell, Polly and Kovrizhinykh, 1996. Late Cretaceous and Paleocene vertebrate paleontology and stratigraphy in the northeastern Aral Sea region, Kazakstan. Journal of Vertebrate Paleontology. 16(3), 46A.
Dong, 1997. On small theropods from Mazongshan area, Gansu province, China. In Dong (ed.). Sino-Japanese Silk Road Dinosaur Expedition. China Ocean Press. 13-18.
Varricchio, 1997. Troodontidae. In Currie and Padian (eds.). Encyclopedia of Dinosaurs. 749-754.
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Sereno, 1998. A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen. 210(1), 41-83.
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Franco, 1999. Dentes de teropodomorfos do Cretáceo Superior da Bacia do Paraná. Análise em Microscopia Eletrônica de Varredura. Masters thesis, Universidade Estadual Paulista. 113 pp.
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"Paronychodontidae"
Diagnosis- basoapical fluting on lateral teeth.
Comments- This family has yet to be officially named, but appears in quotes in Ruiz-Omenaca et al. (1998), Pereda Suberbiola (1999) and Canudo and Ruiz-Omenaca (2003).
Reference- Ruiz-Omeñaca, Canudo, Cuenca-Bescós and Amo, 1998. Theropod teeth from the Lower Cretaceous of Galve (Teruel, Spain). Third European Workshop on Vertebrate Paleontology. 62-63.
Pereda Suberbiola, 1999. Las faunas Finicretacicas de dinosaurios Ibericos. Zubia. 17, 259-279.
Canudo and Ruiz-Omenaca, 2003. Los restos directos de dinosaurios teropódos (excluyendo Aves) en España. Ciencias de la Tierra. 26, 347-373.

unnamed 'paronychodontid' (Zinke and Rauhut, 1994)
Early Kimmeridgian, Late Jurassic
Alcobaca Formation, Portugal
Material- (IPFUB GUI D 1) dentary fragment, three teeth (Zinke and Rauhut, 1994)
(IPFUB GUI D 2) maxillary tooth (1.65 mm) (Zinke and Rauhut, 1994)
(IPFUB GUI D 3) tooth (Zinke and Rauhut, 1994)
(IPFUB GUI D 4-27) twenty-seven teeth (~1.67 mm) (Zinke, 1998)
Comments- IPFUB GUI D 1-3 teeth are recurved with one to two labial ridges and one to four lingual ridges. They have distal serrations which vary in size (6.5/mm in a tooth from GUI D 1; 14/mm in GUI D 2; 31/mm in GUI D 3), though they increase in size basally. GUI D 2 may have a slight basal constriction, and GUI D 3 is not flattened lingually. The mesial carina is unserrated (GUI D 2, GUI D 3), though GUI D 1 has small pits apically that may be worn serrations. Zinke notes all specimens have serrated distal carinae (6-13/mm) and some have serrated mesial carinae (~18/mm). They were identified by Zinke and Rauhut as cf. Paronychodon sp..
References- Zinke and Rauhut, 1994. Small theropods (Dinosauria, Saurischia) from the Upper Jurassic and Lower Cretaceous of the Iberian peninsula. Berliner geowissenschaftliche Abhandlungen, E. 13, 163-177.
Zinke, 1998. Small theropod teeth from the Upper Jurassic coal mine of Guimarota (Portugal). Palaontologische Zeischrift. 72(1/2), 179-189.

unnamed 'paronychodontid' (Ruiz-Omeñaca, Canudo, Cuenca-Bescós and Amo, 1998)
Late Hauterivian-Early Barremian, Early Cretaceous
Castellar Formation, Spain
Material- (MPZ 98-11) tooth (5.32 mm)
Comments- Though this tooth has two ridges on both lingual and labial sides and no mesial serrations, it also has distal serrations (6/mm), so is here excluded from Paronychodon.
References- Ruiz-Omeñaca, Canudo, Cuenca-Bescós and Amo, 1998. Theropod teeth from the Lower Cretaceous of Galve (Teruel, Spain). Third European Workshop on Vertebrate Paleontology. 62-63.
Ruiz-Omenaca, 2006. Restos directos de dinosaurios (Saurischia, Ornithischia) en el Barremiense (Cretacico Inferior) de la Cordillera Iberica en Aragon (Teruel, Espana). PhD Thesis. Universidad de Zaragoza. 584 pp.

unnamed 'paronychodontid' (Zinke and Rauhut, 1994)
Early Barremian, Early Cretaceous
Camarillas Formation, Spain
Material- (JHM POCA-H7) anterior tooth (3.3 mm)
(JHM POCA-H8) lateral tooth (2.08 mm)
Comments- These teeth have 2-3 labial ridges and 3-4 lingual ridges. They lack mesial serrations, and have weak distal serrations (14-16/mm). Distal serrations are rounded and directed slightly apically.
References- Zinke and Rauhut, 1994. Small theropods (Dinosauria, Saurischia) from the Upper Jurassic and Lower Cretaceous of the Iberian Peninsula. Berliner geowiss. Abh.. E 13, 163-177.
Ruiz-Omenaca, 2006. Restos directos de dinosaurios (Saurischia, Ornithischia) en el Barremiense (Cretacico Inferior) de la Cordillera Iberica en Aragon (Teruel, Espana). PhD Thesis. Universidad de Zaragoza. 584 pp.

unnamed 'paronychodontid' (Pol, Buscalioani, Carballeira, Frances, Martinez, Marandat, Moratalla, Sanz, Sige and Villatte, 1992)
Maastrichtian, Late Cretaceous
Calizas de Lychnus Formation, Spain
Material- four teeth
Comments- These teeth were reported as cf. Paronychodon by Pol et al. (1992), then referred to cf. Euronychodon sp. by Canudo and Ruiz-Omenaca (2003), but they differ from both lacustris and portucalensis in being serrated distally.
References- Pol, Buscalioani, Carballeira, Frances, Martinez, Marandat, Moratalla, Sanz, Sige and Villatte, 1992. Reptiles and mammals from the Late Cretaceous new locality Quintanilla del Coco (Burgos Province, Spain). Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 184(3), 279-314.
Canudo and Ruiz-Omenaca, 2003. Los restos directos de dinosaurios teropódos (excluyendo Aves) en España. Ciencias de la Tierra. 26, 347-373.

Paronychodon Cope, 1876
= Euronychodon Antunes and Sigogneau-Russell, 1991
= "Plesiosaurodon" Nessov vide Sues and Averianov, 2013
Diagnosis- serrations absent from teeth.
Comments- This genus is here restricted to 'paronychodontid' teeth without serrations mesially or distally, following Currie et al. (1990). Estes (1964) included serrated specimens with ridges and flattened lingual sides in the genus as well, though these are here referred to Zapsalis abradens (= Saurornitholestes spp. and ?Dromaeosaurus morphotype A of Sankey et al., 2002) and the unnamed troodontid of Sankey et al. (2002). Many unstudied specimens catalogued or listed as Paronychodon probably belong to these two taxa. For instance, one photographed tooth of AMNH 27122 has distal serrations in addition to ridges, so is probably a Zapsalis specimen. Teeth matching the Paronychodon morphotype are known from the Barremian-Maastrichtian of North America and Eurasia, indicating it was probably a clade comparable to theropod families in scope, but which didn't show much dental variation. Once cranial and/or postcranial remains are identified, additional genera of 'paronychodontids' will probably need to be named.
Relationships- Paronychodon was first compared to plesiosaurs by Cope (1876a), who soon (1876b) realized it was theropod based on comparison to Zapsalis. Most authors retain the genus as Theropoda incertae sedis, though some have tried to clarify its relationships further. Estes (1964) referred it to Coeluridae, while Russell (1984) referred it to Dromaeosauridae, and Osmólska and Barsbold (1990) to Troodontidae. These assignments were all done without justification.
More recently, Zinke and Rauhut (1994) suggested a sister group relationship to troodontids based on the large apically angled distal serrations of the Guimarota 'paronychodontid' teeth and the basal constriction in some teeth. These characters are now known in basal dromaeosaurids too (e.g. Microraptor). Rauhut and Zinke (1995) suggested assigning Una Formation Paronychodon teeth to Pelecanimimus, but Rauhut later (2002) considered this unlikely after communication with Perez-Moreno.
Rauhut suggested instead that at least the Una Paronychodon could be archaeopterygids, based on the constricted base, lingually bent carinae (forming mesial and distal grooves along the carinae lingually), and labiodistally twisted tips. Yet the last two characters have yet to be reported from Late Cretaceous Paronychodon, which differs from the Una specimens in several details in any case.
Another hypothesis was given in an abstract by Sankey (2002), who purported to show that Paronychodon is a morphotype of Richardoestesia? isosceles, based on morphology and relative abundance. The details of this study have yet to be published, though it does make sense stratigraphically, as both taxa first appear in Late Jurassic Europe and spread to North America in the Albian, with Late Cretaceous examples known from the Western North America, Central Asia and Europe. It's also logical anatomically, as Richardoestesia? isosceles would be expected to have some unserrated and possibly constricted teeth if it were microraptorian. It should be noted Paronychodon has priority over Richardoestesia, and lacustris and caperatus both have priority over isosceles. Also, Euronychodon has priority over Asiamericana, and portuculensis has priority over both asiatica and asiaticus. So if this synonymy is proven, none of the names associated with straight-toothed Richardoestesia will survive synonymization. Longrich (2008) proposed such a synonymy based on the weak longitudinal ridges on some Richardoestesia teeth, but Larson (2008) noted other contemporaneous theropods sometimes have weak ridges too (tyrannosaurids, 'velociraptorines') and that varied morphologies probably reflect positional variation in Paronychodon teeth. Thus it is unlikely they existed in the same jaws as Richardoestesia teeth.
Sues and Averianov (in prep.) will propose that Paronychodon are juvenile deinonychosaurs, probably in part based on Zapsalis-like specimens which mix 'paronychodontid' longitudinal ridges with dromaeosaurid-like serrations and are dromaeosaurid premaxillary teeth (Currie and Evans, 2019). It is true that Paronychodon teeth are smaller than Dromaeosaurus teeth in the Dinosaur Park Formation, for instance, and that embryonic Troodon has serrationless teeth. This has not been published besides a mention by Averianov (2007) though, so is difficult to evaluate. Similarly, Kirkland (pers. comm. to Demirjian, 9-2019) stated "Baby Utahraptor premaxilla are comparable to "Paranychodon."", giving more credance to the idea.
Hwang (2005, 2007) found that Paronychodon teeth are identical in enamel microstructure to serrationless troodontids like Byronosaurus and IGM 100/1323, while Richardoestesia more closely matched dromaeosaurids. Thus they are here placed as basal troodontids.
Pachycephalosaur fangs?- An odd possibility was suggested by Olshevsky (DML, 1997), that some Paronychodon specimens, including the holotype, may be anterior dentary fangs of "homalocephalid" pachycephalosaurs (cf. Goyocephale) . However, the dentary fangs of Goyocephale are serrated distally, polygonal in section, have a bulbous root, and seem to only possess one lingual ridge. Premaxillary teeth of Goyocephale are somewhat similar to type B teeth of Paronychodon, but lack ridges, are much less labiolingually compressed, and have distal serrations apically. Stegoceras teeth are even less similar, being serrated both mesially and distally with no ridges. The supposed Middle Jurassic pachycephalosaur Ferganocephale has vertical enamel ridges on the base of one side and lacks serrations, but is otherwise highly distinct, being unrecurved, short and uncompressed labiolingually, with a prominent cingulum. The ridges radiate from the base instead of the apex and the entire tooth shape is distinctively ornithischian. Besides the anatomical differences, stratigraphically Paronychodon and "homalocephalids" are also mismatched, with the latter only known from the Campanian-Maastrichtian of Mongolia and perhaps China. The utter lack of "homalocephalids" in well sampled strata like the Dinosaur Park Formation is particularily telling. Also notable is that each "homalocephalid" only had eight fang-like teeth, but had around sixty-six leaf-shaped teeth. So we would expect more pachycephalosaur teeth by a factor of 8:1 or so (even more in Maastrichtian formations where pachycephalosaurines dominate, with no premaxillary teeth and greater numbers of cheek teeth), but Baszio (1997) showed this is not the case. For instance, he recorded 12 Paronychodon teeth from the Dinosaur Park Formation, and only 16 pachycephalosaur teeth. Similarly, Baszio recorded 84 Paronychodon teeth from the Milk River Formation, but only 16 pachycephalosaur teeth. Finally, Zinke and Rauhut (1994) described 'paronychodontid' teeth within a theropod dentary fragment, though these differ from Paronychodon in some details.
Junior synonyms?- Zapsalis was based on a tooth described by Cope (1876) and synonymized with Paronychodon lacustris by Estes (1964). However, Zapsalis falls outside the current concept of Paronychodon in having serrations, and is more robust than teeth of that genus as well. Instead it matches ?Dromaeosaurus morphotype A of Sankey et al. (2002) and was recently found by Currie and Evans (2019) to be identical to premaxillary teeth of Saurornitholestes. Bambiraptor and Velociraptor also have lingual ridges, so that Zapsalis is here considered a morphotype of dromaeosaurid premaxillary teeth.
Tripriodon was based on teeth assigned to two species by Marsh (1889)- the genotype T. coelatus, and T. caperatus. The former is a junior synonym of the multituberculate Meniscoessus robustus (as first shown by Osborn, 1891), while the second belongs to Paronychodon (as first shown by Estes, 1964). Estes was incorrect in synonymizing Tripriodon itself with Paronychodon however, as T. caperatus is only a referred species. This also prevents Marsh's Tripriodontidae from being a theropod family.
Three teeth were originally referred to Paronychodon lacustris (Antunes and Brion, 1988), but later described as the new genus Euronychodon by Antunes and Sigogneau-Russell (1992). This was based on the supposed absence of longitudinal depressions and a median ridge. Yet longitudinal depressions appear to be present in the figure, while identical ridge patterns are seen in some Paronychodon teeth (e.g. Milk River specimens). Euronychodon is thus retained as a junior synonym of Paronychodon here (as in Sige et al., 1997, Rauhut, 2002 and Sues and Averianov, 2013). Numerous other teeth were later referred to Euronychodon from the Barremian-Maastrichtian of Eurasia, but they are here listed as Paronychodon or unnamed 'paronychodontids'.
Variation- Sankey et al. (2002) showed there are two morphotypes of Paronychodon teeth. Type A teeth are elongate and straighter, with unconstricted bases. Type B teeth are short and strongly recurved, with constricted bases. They interpreted these are being due to positional variation instead of taxonomic varation, though it should be noted that the holotypes of both Paronychodon lacustris and Tripriodon caperatus are type A teeth. Thus if taxonomic variation proves correct, these names should only be associated with type A teeth. Based on comparison to other theropods, type B teeth may be more posterior in position.
Baszio (1997) noted that half the teeth are flat lingually, and the other half are biconvex. He considered this due to positional variation, with biconvex teeth being from the posterior portion of the jaw. The FABL, BW and FABL/BW measurements of lingually flat teeth were not significantly different from those of biconvex teeth. Again, the holotypes of both Paronychodon lacustris and Tripriodon caperatus are flattened lingually, which should restrict the names to lingually flat teeth if the variation is later shown to be taxonomic.
References- Cope, 1876a. Descriptions of some vertebrate remains from the Fort Union Beds of Montana. Proceedings of the Academy of Natural Sciences of Philadelphia. 28, 248-261.
Cope, 1876b. On some extinct reptiles and batrachia from the Judith River and Fox Hills Beds of Montana. Proceedings of the Academy of Natural Sciences, Philadelphia. 28, 340-359.
Marsh, 1889. Discovery of Cretaceous mammalia. American Journal of Science, 3rd series. 38, 81-92.
Osborn, 1891. A review of the "Discovery of the Cretaceous Mammalia". The American Naturalist. 25(295), 595-611.
Estes, 1964. Fossil vertebrates from the Late Cretaceous Lance Formation, eastern Wyoming. University of California Publications in Geological Sciences. 49, 1-180.
Russell, 1984. A check list of the families and genera of North American dinosaurs. Syllogeus. 53, 1-35.
Antunes and Brion, 1988. Le Cretace terminal de Beira Litoral, Portugal: remarques stratigraphicques et ecologiques, etude complementaire de Rosasia soutoi (Chelonii, Bothremydidate). Ciencias de Terra. 9, 153-200.
Osmólska and Barsbold, 1990. Troodontidae. In Weishampel, Dodson, and Osmólska, eds.. The Dinosauria, Berkeley: University of California Press: 259-268.
Antunes and Sigogneau-Russell, 1992. La faune de petits dinosaures du Cretace Terminal Portugais. Comun. Serv. Geol. Portugal. 78(1), 49-62.
Zinke and Rauhut, 1994. Small theropods (Dinosauria, Saurischia) from the Upper Jurassic and Lower Cretaceous of the Iberian Peninsula. Berliner geowiss. Abh.. E 13, 163-177.
Rauhut and Zinke, 1995. A description of the Barremian dinosaur fauna from Una with a comparison to that of Las Hoyas. In II International Symposium on Lithographic Limestones, Lleida-Cuenca (Spain), 9th–16th July 1995, Extended Abstracts. 123-126.
Baszio, 1997. Investigations on Canadian dinosaurs: systematic palaeontology of isolated dinosaur teeth from the Latest Cretaceous of south Alberta, Canada. Courier Forschungsinstitut Senckenberg. 196, 33-77.
Olshevsky, DML 1997. https://web.archive.org/web/20190623204714/http://dml.cmnh.org/1997Dec/msg00058.html
Sige, Buscalioni, Duffaud, Gayet, Orth, Rage and Sanz, 1997. Etat des données sur le gisement Crétacé supérieur continental de Champ-Garimond (Gard, Sud de la France). Munchner Geowiss.. 34, 111-130.
Rauhut, 2002. Dinosaur teeth from the Barremian of Una, Province of Cuenca, Spain. Cretaceous Research. 23, 255-263.
Sankey, 2002. Theropod dinosaur diversity in the latest Cretaceous (Maastrichtian) of North America. Journal of Vertebrate Paleontology. 22(3), 103A.
Sankey, Brinkman, Guenther and Currie, 2002. Small theropod and bird teeth from the Late Cretaceous (Late Campanian) Judith River Group, Alberta. Journal of Paleontology. 76(4), 751-763.
Hwang, 2005. Phylogenetic patterns of enamel microstructure in dinosaur teeth. Journal of Morphology. 266, 208-240.
Averianov, 2007. Theropod dinosaurs from Late Cretaceous deposits in the northeastern Aral Sea region, Kazakhstan. Cretaceous Research.
Hwang, 2007. Phylogenetic patterns of enamel microstructure in dinosaur teeth. PhD thesis. Columbia University. 274 pp.
Larson, 2008. Diversity and variation of theropod dinosaur teeth from the uppermost Santonian Milk River Formation (Upper Cretaceous), Alberta: a quantitative method supporting identification of the oldest dinosaur tooth assemblage in Canada. Canadian Journal of Earth Science. 45, 1455-1468.
Longrich, 2008. Small theropod teeth from the Lance Formation of Wyoming, USA. in Sankey and Baszio (eds). Vertebrate Microfossil Assemblages: Their Role in Paleontology and Paleobiogeography. Indiana University Press, Bloomington, Ind.. pp. 135-158.
Sues and Averianov, 2013. Enigmatic teeth of small theropod dinosaurs from the Upper Cretaceous (Cenomanian–Turonian) of Uzbekistan. Canadian Journal of Earth Sciences. 50, 306-314.
Currie and Evans, 2019. Cranial anatomy of new specimens of Saurornitholestes langstoni (Dinosauria, Theropoda, Dromaeosauridae) from the Dinosaur Park Formation (Campanian) of Alberta. The Anatomical Record. DOI: 10.1002/ar.24241
P. lacustris Cope, 1876
Late Campanian, Late Cretaceous
Judith River Formation, Montana, US
Holotype- (AMNH 3018) type A tooth (10 mm)
Referred - (AMNH 8522) type A tooth (13 mm) (Sahni, 1972)
(AMNH 8523) type B tooth (4.8 mm) (Sahni, 1972)
(AMNH 8524) nine teeth (Sahni, 1972)
(AMNH coll.) seven teeth (Sahni, 1972)
(MOR 017) tooth (MOR online)
Early Campanian, Late Cretaceous
Milk River Formation, Alberta, Canada
Material- (CMN coll.) teeth (Russell, 1935)
(UA MR-4: 46) tooth (Baszio, 1997)
(UA MR-47) tooth (Baszio, 1997)
(UA MR-48) type B tooth (Baszio, 1997)
(UA MR-49) type A tooth (Baszio, 1997)
(UA MR-50) type A tooth (Baszio, 1997)
(UA MR-51) type A tooth (Baszio, 1997)
(UA MR-52) tooth (Baszio, 1997)
(UA MR-53) type A tooth (Baszio, 1997)
(UA MR-54) type A tooth (Baszio, 1997)
Late Campanian, Late Cretaceous
Dinosaur Park Formation of the Judith River Group, Alberta, Saskatchewan, Canada
Material- (RTMP 83.36.8) type A tooth (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 84.36.53) type A tooth (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 86.57.62) type A tooth (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 86.60.114) tooth (Ryan and Russell, 2001)
(RTMP 87.19.65) type B tooth (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 87.112.11) type B tooth (4.3 mm) (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 88.211.66) type A tooth (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 94.12.187) type A tooth (11.5 mm) (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 95.145.53) type B tooth (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 95.177.50) type B tooth (~5.2 mm) (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 95.187.28) type B tooth (5.1 mm) (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 99.55.61) type A tooth (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 99.55.230) type A tooth (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 2000.19.2) type B tooth (5.2 mm) (Sankey, Brinkman, Guenther and Currie, 2002)
nine teeth (Baszio, 1997)
material (Tokaryk, 1988)
Late Campanian, Late Cretaceous
De-na-zin Member of the Kirtland Formation, New Mexico, US
Material- (SMP VP-1354) tooth (Sullivan and Lucas, 2006)
Late Maastrichtian, Late Cretaceous
Frenchman Formation, Saskatchewan, Canada
Material- four teeth (Baszio, 1997)
Diagnosis- (after Sahni, 1972) smaller than P. caperatus and with less defined ridges.
Comments- The holotype has a FABL of 4 mm and a BW of 2.4 mm. It is recurved and flattened lingually with four lingual ridges and six labial ridges. Serrations are absent. It is not from the Hell Creek Formation, contra some sources. Though Sankey et al. (2002) claimed it is not illustrated, Glut (1997) included a photo. Note the collection number also includes other material such as the incomplete theropod tibia photographed on the AMNH database website. Baszio (1997) stated that Paronychodon teeth from the Judith River Group, Milk River Formation and Frenchman Formations were identical. Sullivan and Lucas (2006) in turn stated that SMP VP-1354 from the Kirtland Formation is identical to Milk River teeth. All of these are smaller and with less defined ridges than the Lance Formation species. They can be referred to the species P. lacustris, while the Lance Formation material can be referred to P. caperatus. It's probable other Campanian-Maastrichtian Paronychodon remains (listed as P. sp. below) will be referrable to P. lacustris once they are examined in more detail. Furthermore, this P. lacustris morphotype probably belonged to several different species which differed in non-dental characters, which explains its apparently wide distribution.
References- Cope, 1876. Descriptions of some vertebrate remains from the Fort Union Beds of Montana. Proceedings of the Academy of Natural Sciences of Philadelphia. 28, 248-261.
Russell, 1935. Fauna of the Upper Milk River beds, Southern Alberta. Transactions, Royal Society of Canada. 3(29), 115-127.
Sahni, 1972. The vertebrate fauna of the Judith River Formation, Montana. Bulletin of the AMNH. 147.
Tokaryk, 1988. Preliminary vertebrate faunal list of the Oldman Formation Saskatchewan. Journal of Vertebrate Paleontology. 8(3), 28A.
Baszio, 1997. Investigations on Canadian dinosaurs: systematic palaeontology of isolated dinosaur teeth from the Latest Cretaceous of south Alberta, Canada. Courier Forschungsinstitut Senckenberg. 196, 33-77.
Glut, 1997. Dinosaurs, the Encyclopedia. Mcfarland & Company, Inc.. 1076 pp.
Ryan and Russell, 2001. The dinosaurs of Alberta (exclusive of Aves). in Tanke and Carpenter (eds.). Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie. Indiana University Press, Bloomington, Indiana. pp. 279-297.
Sankey, Brinkman, Guenther and Currie, 2002. Small theropod and bird teeth from the Late Cretaceous (Late Campanian) Judith River Group, Alberta. Journal of Paleontology. 76(4), 751-763.
Sullivan and Lucas, 2006. The Kirtlandian land-vertebrate "age" - faunal composition, temporal position and biostratigraphic correlation in the nonmarine Upper Cretaceous of western North America. New Mexico Museum of Natural History and Science Bulletin. 35, 7-29.
P. caperatus (Marsh, 1889) Olshevsky, 1991
= Tripriodon caperatus Marsh, 1889
= Menisocoessus caperatus (Marsh, 1889)
= Dipriodon caperatus (Marsh, 1889) Currie, Rigby and Sloan, 1990
Late Maastrichtian, Late Cretaceous
Lance Formation, Wyoming, US
Holotype- (YPM 10624; = YPM 11852) type A tooth
Referred- (AMNH 21550) tooth (AMNH online)
(AMNH 21551) tooth (AMNH online)
(AMNH 21811) twenty-four teeth (AMNH online)
(AMNH 21812) sixteen teeth and fragments (AMNH online)
(AMNH 21813) sixteen teeth (AMNH online)
(AMNH 21814) three teeth (AMNH online)
?(AMNH 21881) two teeth (AMNH online)
?(AMNH 21882) sixteen teeth (AMNH online)
?(AMNH 21883) tooth (AMNH online)
(AMNH 24930) eighteen teeth (AMNH online)
?(AMNH 24931) tooth (AMNH online)
?(AMNH 24932) four teeth (AMNH online)
(AMNH 27122 in part) sixteen teeth and fragments (AMNH online)
?(AMNH coll.) teeth (Estes, 1964)
(SDSM 12459) two teeth (Whitmore, 1988)
(SDSM 12460) tooth (Whitmore, 1988)
(SDSM 12461) tooth (Whitmore, 1988)
(SDSM 12707) tooth (Whitmore, 1988)
(SDSM 15101) tooth fragment (Whitmore, 1988)
(UA BTB: 134) tooth (Baszio, 1997)
(UA BTB: 136) tooth (Baszio, 1997)
(UA BTB: 137) tooth (Baszio, 1997)
(UA BTB: 138) type A tooth (Baszio, 1997)
(UA BTB: 146) tooth (Baszio, 1997)
?(UA BTB: 166) type B tooth (Baszio, 1997)
(UA BTB: coll.) tooth (Baszio, 1997)
(UCM 38288) (juvenile) tooth (4 mm) (Carpenter, 1982)
(UCM 38459) (juvenile) tooth (1.7 mm) (Carpenter, 1982)
(UCMP 53283) tooth (UCMP online)
(UCMP 73075) teeth (UCMP online)
(UCMP 73076) teeth (UCMP online)
(UCMP 85135) tooth (UCMP online)
(UCMP 124400) three teeth (UCMP online)
(UCMP 124401) four teeth (UCMP online)
(UCMP 186863) teeth (UCMP online)
(UCMP 186919) teeth (UCMP online)
(UCMP 187085-187134) fifty teeth (UCMP online)
(UW 14091) tooth (Breithaupt, 1982)
(UW 14092) tooth (Breithaupt, 1982)
?(YPM 10625) tooth (Marsh, 1889)
?(YPM 54481) (YPM online)
?(YPM 54490) (YPM online)
(YPM 54999) (YPM online)
(YPM 55021) (YPM online)
(YPM 55022) (YPM online)
(YPM 55498) (YPM online)
?(YPM 55501) (YPM online)
(YPM 55514) (YPM online)
?(YPM 55517) (YPM online)
?(YPM 55527) (YPM online)
(YPM 55528) (YPM online)
?(YPM 55533) (YPM online)
(YPM 55547) (YPM online)
(YPM 55548) (YPM online)
?(YPM 55585) (YPM online)
(YPM 55594) (YPM online)
(YPM 10630) partial type A tooth (Marsh, 1889)
(YPM coll.) tooth (Osborn, 1891)
tooth (Breithaupt, 2001)
Diagnosis- (after Sahni, 1972) larger than P. lacustris and with better defined ridges.
Comments- Marsh (1889) originally described Tripriodon caperatus based on several teeth and tooth fragments discovered that year, including supposed lower incisors. The holotype is often listed as YPM 11853, but is 11852 in the YPM online catalog. Although Marsh states the specimen came from Laramie beds, the Laramie Formation has not yielded dinosaurs in Wyoming, and the YPM online catalog confirms it was actually found in the Lance Formation. Marsh viewed T. caperatus and the genotype T. coelatus as belonging to a new family Tripriodontidae in his Allotheria, most closely related to Stereognathus (now recognized as a tritylodontid). Tripriodon coelatus is based on a molar which is now thought to belong to Meniscoessus robustus, a species of multituberculate. This was first recognized by Osborn (1891), who believed T. caperatus were lower incisors of Meniscoessus. Osborn also recognized supposed lower incisors of Selenacodon brevis (YPM 10630) and Tripriodon coelatus (YPM coll.) have the same morphology as T. caperatus. Selenacodon brevis is now viewed as a junior synonym of the multituberculate Cimolemys gracilis. Estes (1964) incorrectly believed T. caperatus to be the genotype, and was the first of many authors to synonymize Tripriodon with Paronychodon. He referred the T. caperatus holotype and YPM 10630 to Paronychodon lacustris. Currie et al. (1990) mistakenly listed Dipriodon caperatus, but Dipriodon is another genus now viewed as a synonym of Meniscoessus.
The holotype tooth seems nearly identical to the Paronychodon holotype except for having a shorter crown. It clearly matches tooth type A of Sankey et al. (2002). Baszio (1997) notes these Lance Formation teeth are larger than Paronychodon lacustris from the Milk River, Dinosaur Park, Frenchman and Horseshoe Canyon Formations, with more pronounced wrinkles. They are retained as Paronychodon caperatus here, after Olshevsky (1991). UA BTB 166 is unique in being biconvex with helical ridges.
References- Marsh, 1889. Discovery of Cretaceous Mammalia. American Journal of Science, 3rd series. 38, 81-92.
Osborn, 1891. A review of the "Discovery of the Cretaceous Mammalia". The American Naturalist. 25(295), 595-611.
Estes, 1964. Fossil vertebrates from the Late Cretaceous Lance Formation, eastern Wyoming. University of California Publications in Geological Sciences. 49, 1-180.
Breithaupt. 1982. Paleontology and paleoecology of the Lance Formation, (Maastrichtian), east flank of Rick Springs Uplift, Sweetwater County, Wyoming. Contributions to Geology, University of Wyoming. 21(2), 123-151.
Carpenter, 1982. Baby dinosaurs from the Late Cretaceous Lance and Hell Creek formations and a description of a new species of theropod. Contributions to Geology, University of Wyoming. 20(2), 123-134.
Whitmore, 1988. The vertebrate paleontology of Late Cretaceous (Lancian) localities in the Lance Formation, Northern Niobrara County, Wyoming. Unpublished Masters Thesis. South Dakota School of Mines and Technology, Rapid City, South Dakota. 130pp.
Currie, Rigby and Sloan, 1990. Theropod teeth from the Judith River Formation of southern Alberta, Canada. in Carpenter and Currie (eds.). Dinosaur Systematics: Perspectives and Approaches. Cambridge University Press, New York. pp. 107-125.
Olshevsky, 1991. A Revison of the Parainfraclass Archosauria Cope, 1869, Excluding the Advanced Crocodyila. Mesozoic Menanderings #2 (1st printing). iv + 196pp.
Baszio, 1997. Investigations on Canadian dinosaurs: systematic palaeontology of isolated dinosaur teeth from the Latest Cretaceous of south Alberta, Canada. Courier Forschungsinstitut Senckenberg. 196, 33-77.
Breithaupt, 2001. Passport-in-time microvertebrate fossil project at the University of Wyoming Geological Museum: Late Cretaceous Paleontological resources in the public eye. in Santucci and McClelland (eds). Proceedings of the 6th fossil resource conference. United States Department of the interior, National Park Service, Geological Resource Division. 107-112.
Sankey, Brinkman, Guenther and Currie, 2002. Small theropod and bird teeth from the Late Cretaceous (Late Campanian) Judith River Group, Alberta. Journal of Paleontology. 76(4), 751-763.
Stokosa 2005. Enamel microstructure variation within the Theropoda. in Carpenter (ed). The Carnivorous Dinosaurs. 163-178.
P. sp. (Peng, Russell and Brinkman, 2001)
Late Campanian, Late Cretaceous
Foremost Formation of the Judith River Group, Alberta, Canada
Material- (RTMP 96.62 coll.) three teeth
Reference- Peng, Russell and Brinkman, 2001. Vertebrate microsite assemblages (exclusive of mammals) from the Foremost and Oldman Formations of the Judith River Group (Campanian) of southeastern Alberta: An illustrated guide. Provincial Museum of Alberta Natural History Occasional Paper. 25, 54 pp.
P. sp. (Ryan and Russell, 2001)
Late Campanian, Late Cretaceous
Oldman Formation of the Judith River Group, Alberta, Canada
Material- (RTMP 92.77.6) tooth
(RTMP coll.) teeth
Reference- Ryan and Russell, 2001. The dinosaurs of Alberta (exclusive of Aves). in Tanke and Carpenter (eds.). Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie. Indiana University Press, Bloomington, Indiana. pp. 279-297.
P. sp. (Fanti and Miyashita, 2009)
Late Campanian, Late Cretaceous
Wapiti Formation, Alberta, Canada
Material- (UALVP 48815) tooth (3.9x2.3x1.1 mm)
Reference- Fanti and Miyashita, 2009. A high latitude vertebrate fossil assemblage from the Late Cretaceous of west-central Alberta, Canada: Evidence for dinosaur nesting and vertebrate latitudinal gradient. Palaeogeography, Palaeoclimatology, Palaeoecology. 275, 37-53.
P. sp. (Baszio, 1997)
Early Maastrichtian, Late Cretaceous
Horseshoe Canyon Formation, Alberta, Canada
Material- (RTMP 97.39.6) partial type A tooth (Ryan, Currie, Gardner, Vickaryous and Lavigne, 1998)
(RTMP 1041) tooth (Baszio, 1997)
(RTMP 2009.139.4) tooth (Larson, Brinkman and Bell, 2010)
Comments- RTMP 97.39.6 is flat lingually and convex labially. It has eight lingual ridges and ten labial ones. RTMP 2009.139.4 also has that convexity, but also faint serrations.
References- Baszio, 1997. Investigations on Canadian dinosaurs: systematic palaeontology of isolated dinosaur teeth from the Latest Cretaceous of south Alberta, Canada. Courier Forschungsinstitut Senckenberg. 196, 33-77.
Ryan, Currie, Gardner and Livigne, 1997. Baby hadrosaurid material associated with an unusually high abundance of troodontid teeth from the Horseshoe Canyon Formation (Early Maastrichtian), Alberta, Canada. Journal of Vertebrate Paleontology. 17(3), 72A.
Ryan, Currie, Gardner, Vickaryous and Lavigne, 1998. Baby hadrosaurid material associated with an unusually high abundance of Troodon teeth from the Horseshoe Canyon Formation, Upper Cretaceous, Alberta, Canada. Gaia. 15, 123-133.
Larson, Brinkman and Bell, 2010. Faunal assemblages from the upper Horseshoe Canyon Formation, an early Maastrichtian cool-climate assemblage from Alberta, with special reference to the Albertosaurus sarcophagus bonebed. Canadian Journal of Earth Sciences. 47(9), 1159-1181.
P? sp. (Krumenacker and Scofield, 2015)
Late Albian-Cenomanian, Early-Late Cretaceous
Wayan Formation, Idaho, US
Material- (IMNH 2251/49862; Morph 5) tooth (?x~6.2x? mm)
References- Krumenacker and Scofield, 2015. A diverse theropod tooth assemblage from the Mid-Cretaceous (Albian-Cenomanian) Wayan Formation of Idaho. Journal of Vertebrate Paleontology. Program and Abstracts 2015, 158.
Krumenacker, Simon, Scofield and Varricchio, 2016. Theropod dinosaurs from the Albian-Cenomanian Wayan Formation of eastern Idaho. Historical Biology. DOI: 10.1080/08912963.2015.1137913
P. sp. (Redman, Moore and Varricchio, 2015)
Late Campanian, Late Cretaceous
Two Medicine Formation, Montana, US
Material- (MOR 221) tooth (MOR online)
(MOR 505) tooth (MOR online)
(MOR 516) teeth (MOR online)
teeth (Redman, Moore and Varricchio, 2015)
Reference- Redman, Moore and Varricchio, 2015. A new vertebrate microfossil locality in the Upper Two Medicine Formation in the vicinity of Egg Mountain. Journal of Vertebrate Paleontology. Program and Abstracts 2015, 201-202.
P. sp. (Estes, Berberian and Mesozoely, 1969)
Late Maastrichtian, Late Cretaceous
Hell Creek Formation, Montana, South Dakota, US
Material- (AMNH 21555) tooth (AMNH online)
(MCZ 3645) two teeth (Estes, Berberian and Mesozoely, 1969)
(UCMP 119922) tooth (UCMP online)
(UCMP 119923) tooth (UCMP online)
(UCMP 120076) tooth (UCMP online)
(UCMP 120192) tooth (UCMP online)
(UCMP 120254) tooth fragment (UCMP online)
(UCMP 123341) tooth (UCMP online)
(UCMP 124405) tooth (UCMP online)
(UCMP 124990) (juvenile) type B tooth (3.4 mm) (Carpenter, 1982)
(UCMP 124991) (juvenile) tooth (4.8 mm) (Carpenter, 1982)
(UCMP 124992) (juvenile) tooth (4.3 mm) (Carpenter, 1982)
(UCMP 128764) three teeth (UCMP online)
(UCMP 186867) teeth (UCMP online)
(UCMP 186876) teeth (UCMP online)
(UCMP 186879) teeth (UCMP online)
(UCMP 186884) teeth (UCMP online)
(UCMP 186898) teeth (UCMP online)
(UCMP 186910) teeth (UCMP online)
(UCMP 186923) teeth (UCMP online)
(UCMP 187080) tooth (UCMP online)
(UCMP 187081) tooth (UCMP online)
(UCMP 187082) tooth (UCMP online)
(UCMP 187135-187156) twenty-two teeth (UCMP online)
(YPM PU 20571) (Estes, Berberian and Mesozoely, 1969)
(YPM 56974) two teeth (YPM online)
teeth (Stenerson and O'Conner, 1994)
teeth (Triebold, 1997)
teeth (DePalma, 2010)
References- Estes, Berberian and Mesozoely, 1969. Lower vertebrates from the Late Cretaceous Hell Creek Formation, McCone County, Montana. Breviora. 337, 1-33.
Carpenter, 1982. Baby dinosaurs from the Late Cretaceous Lance and Hell Creek formations and a description of a new species of theropod. Contributions to Geology, University of Wyoming. 20(2), 123-134.
Stenerson and O'Conner, 1994. The Late Cretaceous Hell Creek Formation of Northwestern South Dakota and its Fauna. MAPS Digest. 17(4), 108-120.
Triebold, 1997. The Sandy Site: Small Dinosaurs from the Hell Creek Formation of South Dakota. in Wolberg, Stump and Rosenberg (eds). Dinofest International, Proceedings of a Symposium sponsered by Arizona State University. A Publication of The Academy of Natural Sciences. 245-248.
DePalma, 2010. Geology, taphonomy, and paleoecology of a unique Upper Cretaceous bonebed near the Cretaceous-Tertiary boundary in South Dakota. Masters thesis, University of Kansas. 227 pp.
P. sp. indet.
Cretaceous
Montana, US
Material- (AMNH 2134) tooth (AMNH online)
P. sp. (Hoganson and Erickson, 2004)
Maastrichtian, Late Cretaceous
Fox Hills Formation, North Dakota, US
Reference- Hoganson and Erickson, 2004. Paleoecological implications of the Fox Hills Formation (Maastrichtian) reptilian and amphibian fauna from south-central North Dakota. Geological Society of America Rocky Mountain and Cordilleran Sections Annual Meeting, Boise, Idaho, Abstracts with Programs. 36(4), 80.
P. sp. (Breithaupt, 1985)
Late Campanian, Late Cretaceous
Mesaverde Formation, Wyoming, US
Material- (AMNH 12881) tooth (Demar and Breithaupt, 2006)
(AMNH 12882) tooth (Demar and Breithaupt, 2006)
(UCMP 120848) tooth (UCMP online)
(UW 34819) tooth (Demar and Breithaupt, 2006)
References- Breithaupt, 1985. Nonmammalian vertebrates faunas from the late Cretaceous of Wyoming. Thirty-Sixth Annual Field Conference-1985, Wyoming Geological Association Guidebook. 159-175.
Demar and Breithaupt, 2006. The nonmammalian vertebrate microfossil assemblages of the Mesaverde Formation (Upper Cretaceous, Campanian) of the Wind River and Bighorn Basin, Wyoming. in Lucas and Sullivan (eds). Late Cretaceous Vertebrates from the Western Interior. New Mexico Museum of Natural History & Science, Bulletin. 35, 33-53.
P. sp. (Wroblewski, 1995)
Late Maastrichtian, Late Cretaceous
Ferris Formation, Wyoming, US
Material- teeth
References- Wroblewski, 1995. First report of changes in Lower Vertebrate Faunas across the Cretaceous-Tertiary boundary, Western Hanna Basin, Wyoming. Journal of Vertebrate Paleontology. 15(3), 61A.
Wroblewski, 1998. Changing paleoenvironments and paleofaunas across the K-T boundary, Ferris Formation, Southcentral Wyoming. Tate Geological Museum, Casper College, Casper Wyoming. Tate ’98. Life in the Cretaceous. 53-70.
P. sp. (Kirkland, Britt, Burge, Carpenter, Cifelli, DeCourten, Eaton, Hasiotis and Lawton, 1997)
Late Cenomanian, Late Cretaceous
Dakota Formation, Utah, US
Material- teeth
Comments- These were listed as cf. Paronychodon sp. by Kirkland et al. (1997).
Reference- Kirkland, Britt, Burge, Carpenter, Cifelli, DeCourten, Eaton, Hasiotis and Lawton, 1997. Lower to Middle Cretaceous dinosaur faunas of the Central Colorado Plateau: a key to understanding 35 million years of tectonics, sedimentology, evolution, and biogeography. Brigham Young University Geology Studies. 42, 69-103.
P. sp. (Kirkland and Parrish, 1995)
Cenomanian-Early Turonian, Late Cretaceous
Mussentuchit Member of the Cedar Mountain Formation, Utah, US
Material- (CM 72650) tooth fragment (Fiorillo, 1999)
(NCSM 33277) incomplete type B tooth (~3.3x1.57x1.00 mm) (Avrahami, Gates, Heckert, Makovicky and Zanno, 2018)
(NCSM 33298) type A tooth (2.11x1.16x0.77 mm) (Avrahami, Gates, Heckert, Makovicky and Zanno, 2018)
(OMNH coll.) teeth (Kirkland et al., 1997)
partial type A tooth (Garrison et al., 2007)
Comments- Kirkland and Parrish (1995), Kirkland et al. (1997) and Cifelli et al. (1999) list cf. Paronychodon sp. teeth. Kirkland (pers. comm. to Demirjian, 9-2019) stated "Most of these reports were based on studies we did on basal Cenomanian age teeth in the Mussentuchit from the Oklahoma Mus. Nat. History in the 1990s." Fiorillo (1999) describes a tooth fragment possessing a flattened side with longitudinal ridges which he assigns to "Paronychodon", and believes is a dromaeosaurid tooth based on its cross section. Garrison et al. (2007) describes a partial tooth lacking serrations and a flattened side with three ridges, referring it to cf. Paronychodon sp..
References- Kirkland and Parrish, 1995. Theropod teeth from the Lower Cretaceous of Utah. Journal of Vertebrate Paleontology. 15(3), 39A.
Kirkland, Britt, Burge, Carpenter, Cifelli, DeCourten, Eaton, Hasiotis and Lawton, 1997. Lower to Middle Cretaceous dinosaur faunas of the Central Colorado Plateau: a key to understanding 35 million years of tectonics, sedimentology, evolution, and biogeography. Brigham Young University Geology Studies. 42, 69-103.
Cifelli, Nydam, Gardner, Weil, Eaton, Kirkland, Madsen, 1999. Medial Cretaceous vertebrates from the Cedar Mountain Formation, Emery County, Utah: the Mussentuchit Local Fauna. in Gillette (ed.). Vertebrate Paleontology in Utah. Utah Geological Survey, Miscellaneous Publication. 99-1, 219-242.
Fiorillo, 1999. Non-mammalian microvertebrate remains from the Robison Eggshell site, Cedar Mountain Formation (Lower Cretaceous), Emery County, Utah. in Gillette (ed.). Vertebrate Paleontology in Utah. Utah Geological Survey, Miscellaneous Publication. 99-1, 259-268.
Garrison, Brinkman, Nichols, Layer, Burge and Thayn, 2007. A multidisciplinary study of the Lower Cretaceous Cedar Mountain Formation, Mussentuchit Wash, Utah: a determination of the paleoenvironment and paleoecology of the Eolambia caroljonesa dinosaur quarry. Cretaceous Research. 28, 461-494.
Avrahami, 2018. Paleobiodiversity of a new microvertebrate locality from the Upper Cretaceous Mussentuchit Member, Cedar Mountain Formation, Utah: Testing morphometric multivariate approaches for quantifying shape variation in microvertebrate specimens. Masters thesis, North Carolina State University. 181 pp.
Avrahami, Gates, Heckert, Makovicky and Zanno, 2018. A new microvertebrate assemblage from the Mussentuchit Member, Cedar Mountain Formation: Insights into the paleobiodiversity and paleobiogeography of early Late Cretaceous ecosystems in western North America. PeerJ. 6:e5883.
P. sp. (Kirkland, Lucas and Estep, 1998)
Middle-Late Turonian, Late Cretaceous
Smoky Hollow Member of the Straight Cliffs Formation, Utah, US
Material- (MNA 995) tooth (Parrish, 1999)
(OMNH 24451) tooth (Parrish, 1999)
(OMNH 25415) tooth (Parrish, 1999)
Comments- These were listed as cf. Paronychodon by Kirkland et al. (1998) and Parrish (1999).
References- Kirkland, Lucas and Estep, 1998. Cretaceous dinosaurs of the Colorado Plateau. in Lucas, Kirkland and Estep (eds.). Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science Bulletin. 14, 79-89.
Parrish, 1999. Dinosaur teeth from the Upper Cretaceous (Turonian-. Judithian) of southern Utah. in Gillette (ed.). Vertebrate Paleontology in Utah. Utah Geological Survey, Miscellaneous Publication. 99-1, 319-321.
P. sp. (Kirkland, Lucas and Estep, 1998)
Coniacian-Santonian, Late Cretaceous
John Henry Member of the Straight Cliffs Formation, Utah, US
Comments- This is listed as cf. Paronychodon sp. by Kirkland et al. (1998).
Reference- Kirkland, Lucas and Estep, 1998. Cretaceous dinosaurs of the Colorado Plateau. in Lucas, Kirkland and Estep (eds.). Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science Bulletin. 14, 79-89.
P. sp. (Kirkland, Lucas and Estep, 1998)
Early Campanian, Late Cretaceous
Wahweap Formation, Utah
Comments- This is listed as cf. Paronychodon sp. by Kirkland et al. (1998).
Reference- Kirkland, Lucas and Estep, 1998. Cretaceous dinosaurs of the Colorado Plateau. in Lucas, Kirkland and Estep (eds.). Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science Bulletin. 14, 79-89.
P. sp. (Kirkland, Lucas and Estep, 1998)
Late Campanian, Late Cretaceous
Kaiparowitz Formation, Utah, US
Material- (UCM 8304) tooth (Parrish, 1999)
(OMNH 24161) tooth (Parrish, 1999)
(OMNH 24164) tooth (Parrish, 1999)
Comments- These were listed as cf. Paronychodon by Kirkland et al. (1998) and Parrish (1999).
Reference- Kirkland, Lucas and Estep, 1998. Cretaceous dinosaurs of the Colorado Plateau. in Lucas, Kirkland and Estep (eds.). Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science Bulletin. 14, 79-89.
Parrish, 1999. Dinosaur teeth from the Upper Cretaceous (Turonian-. Judithian) of southern Utah. in Gillette (ed.). Vertebrate Paleontology in Utah. Utah Geological Survey, Miscellaneous Publication. 99-1, 319-321.
P? sp. (Armstrong-Zeigler, 1978)
Late Campanian, Late Cretaceous
Fossil Forest Member of the Fruitland Formation, New Mexico, US
Material- (MNA Pl. 1627) nine teeth (Armstrong-Ziegler, 1978)
(NMMNH P-27490) tooth (?x1.9x1.2 mm) (Williamson and Brusatte, 2014)
(NMMNH P-30276) tooth (1.8x1.3x.5 mm) (Williamson and Brusatte, 2014)
(NMMNH P-30329) tooth (Williamson and Brusatte, 2014)
(NMMNH P-30332) tooth (Williamson and Brusatte, 2014)
(NMMNH P-33479) tooth (~4.3x2x1.1 mm) (Williamson and Brusatte, 2014)
(NMMNH P-38430) tooth (Williamson and Brusatte, 2014)
(NMMNH P-53360) tooth (Williamson and Brusatte, 2014)
Late Campanian, Late Cretaceous
Hunter Wash Member of Kirtland Formation, New Mexico, US
(NMMNH P-29132) tooth (Williamson and Brusatte, 2014)
(NMMNH P-30218) tooth (2.6x1.5x.8 mm) (Williamson and Brusatte, 2014)
(NMMNH P-30233) tooth (?x2.8x1.5 mm) (Williamson and Brusatte, 2014)
(NMMNH P-30234) tooth (?x2.1x1.1 mm) (Williamson and Brusatte, 2014)
Comments- MNA Pl. 1627 were listed as Paronychodon lacustris by Armstrong-Ziegler (1978), but later as Dromaeosauridae incertae sedis by Lucas et al. (1987). Williamson and Brusatte (2014) note this differs from Dinosaur Park Paronychodon in having "less pronounced apicobasal ridges and in lacking ridges that anastomose from the apex to the base of the crown." Some resemble Zapsalis except for lacking distal serrations, so may belong to that taxon.
References- Armstrong-Zeigler, 1978. An aniliid snake and associated vertebrates from the Campanian of New Mexico. Journal of Paleontology. 52(2), 480-483.
Lucas, Mateer, Hunt and O’Neill, 1987. Dinosaurs, the age of the Fruitland and Kirtland Formations, and the Cretaceous-Tertiary boundary in the San Juan Basin, New Mexico. in Fassett and Rigby (eds). The Cretaceous-Tertiary Boundary in the San Juan and Raton Basins, New Mexico and Colorado. The Geological Society of America Special Paper. 209, 35-50.
Williamson and Brusatte, 2014. Small theropod teeth from the Late Cretaceous of the San Juan Basin, Northwestern New Mexico and their implications for understanding Latest Cretaceous dinosaur evolution. PLoS ONE. 9(4), e93190.
P. sp. (Langston, Standhardt and Stevens, 1989)
Early Maastrichtian, Late Cretaceous
Aguja Formation, Texas, US
Material- (LSU 113:1310) type A tooth (~5.5 mm)
(LSU 113:1311) type A tooth
(LSU 113:5107) type A tooth (~3 mm)
(LSU 113:5993) type A tooth (~2.5 mm)
(LSU 113:5996) type A tooth
References- Langston, Standhardt and Stevens, 1989. Fossil vertebrate collecting in the Big Bend - History and retrospective. in Vertebrate Paleontology, Biostratigraphy and Depositional Environments, Latest Cretaceous and Tertiary, Big Bend Area, Texas. Guidebook Field Trip Numbers 1 a, B, and 49th Annual Meeting of the Society of Vertebrate Paleontology, Austin, Texas, 29 October - 1 November 1989. 11-21.
Sankey, Standhardt and Schiebout, 2005. Theropod teeth from the Upper Cretaceous (Campanian-Maastrichtian), Big Bend National Park, Texas. in Carpenter (ed). The Carnivorous Dinosaurs. 127-152.
P. portucalensis (Antunes and Sigogneau-Russell, 1991) new comb.
= Euronychodon portucalensis Antunes and Sigogneau-Russell, 1991
Late Campanian-Early Maastrichtian, Late Cretaceous
unnamed unit, Taviero, Portugal
Holotype- (CEPUNL TV 20) type A tooth (1.8 mm)
Paratypes- (CEPUNL TV 18) type B tooth
(CEPUNL TV 19) tooth
Diagnosis- provisionally indeterminate within Paronychodon.
Comments- These teeth were originally referred to Paronychodon lacustris (Antunes and Brion, 1988). They were later described as the new genus Euronychodon by Antunes and Sigogneau-Russell (1992) based on the supposed absence of longitudinal depressions and a median ridge. Yet longitudinal depressions appear to be present in the figure, while identical ridge patterns are seen in some Paronychodon teeth (e.g. Milk River specimens). Euronychodon is thus retained as a junior synonym of Paronychodon here (as in Rauhut, 2002).
References- Antunes and Brion, 1988. Le Cretace terminal de Beira Litoral, Portugal: remarques stratigraphicques et ecologiques, etude complementaire de Rosasia soutoi (Chelonii, Bothremydidate). Ciencias de Terra. 9, 153-200.
Antunes and Sigogneau-Russell, 1992. La faune de petits dinosaures du Cretace Terminal Portugais. Comun. Serv. Geol. Portugal. 78(1), 49-62.
Rauhut, 2002. Dinosaur teeth from the Barremian of Una, Province of Cuenca, Spain. Cretaceous Research. 23, 255-263.
P. sp. nov. (Rauhut and Zinke, 1995)
Late Barremian, Early Cretaceous
Una (= Calizas de La Huergina) Formation, Spain
Material- (IPFUB Una Th 53, 55-61, 69) thirteen teeth (to 6 mm) (Rauhut and Zinke, 1995)
(IPFUB Una Th 69) tooth (Rauhut, 2002)
Comments- These teeth are slightly recurved, with no mesial or distal serrations. They have a flattened lingual side with a central ridge, while some specimens also have a weak labial ridge. Some teeth have a slight basal constriction. Rauhut and Zinke (1995) originally referred these specimens to cf. Euronychodon sp., though they were later referred to cf. Paronychodon sp. by Rauhut (2002).
References- Rauhut and Zinke, 1995. A description of the Barremian dinosaur fauna from Una with a comparison to that of Las Hoyas. In II International Symposium on Lithographic Limestones, Lleida-Cuenca (Spain), 9th–16th July 1995, Extended Abstracts. 123-126.
Rauhut, 2002. Microrestos de dinosaurios del Cretácico inferior de Uña, España. Resumenes de las XVIII Jornadas Argentinas de Paleontología de Vertebrados. Bahia Blanca, Argentina. 36.
Rauhut, 2002. Dinosaur teeth from the Barremian of Una, Province of Cuenca, Spain. Cretaceous Research. 23, 255-263.
P? sp. (Le Loeuff, 1992)
Late Campanian, Late Cretaceous
Laño, Sedano Formation, Spain
Material- (MCNA 14562) tooth (1.9x1.3x.9 mm)
(MCNA 14563) tooth (1.8x1.1x.7 mm)
Comments- These were listed as cf. Euronychodon sp. by Suberbiola et al. (2000). Isasmendi et al. (2020) referred at least two of the teeth called Coelurosauria indet. by Torices et al. (2015) to cf. Paronychodon, as they have longitudinal grooves. It is likely more Laño teeth listed under unnamed Maniraptoriformes on this site belong here as well.
References- Le Loeuff, 1992. Les vertébrés continentaux du Crétacé supérieur d'Europe: Paléoécologie, Biostratigraphie et Paléobiogéographie. Mémoires des Sciences de la Terre de l'Université Pierre et Marie Curie, Paris, (Thèse d'Université, non publié). 92-3, 273 pp.
Astibia, Murelaga, Pereda-Suberbiola, Elorza and Gomez-Alday, 1999. Taphonomy and palaeoecology of the Upper Cretaceous continental vertebrate-bearing beds of the Laño Quarry (Iberian Peninsula). Est. Mus. Cienc. Nat. de Alava. 14 (Núm. Espec. 1), 43-104.
Pereda-Suberbiola, Asibia, Murelaga, Elzorza and Gomez-Alday, 2000. Taphonomy of the Late Cretaceous dinosaur-bearing beds of the Laño Quarry (Iberian Peninsula). Palaeogeography, Palaeoclimatology, Palaeoecology. 157, 247-275.
Torices, Currie, Canudo and Pereda-Suberbiola, 2015. Theropod dinosaurs from the Upper Cretaceous of the South Pyrenees Basin of Spain. Acta Palaeontologica Polonica. 60(3), 611-626.
Isasmendi, Torices, Canudo and Pereda-Suberbiola, 2020. Paleobiodiversity of theropod dinosaurs from the Upper Cretaceous Laño site, northern Iberian peninsula. The Society of Vertebrate Paleontology 80th Annual Meeting, Conference Program. 186-187.
P? sp. (Torices, Barroso-Barcenilla, Cambra-Moo, Perez and Serrano, 2011)
Late Campanian-Early Maastrichtian, Late Cretaceous
Villalba de la Sierra Formation, Spain
Material- teeth
Comments- Torices et al. (2011) mention cf. Paronychodon.
Reference- Torices, Barroso-Barcenilla, Cambra-Moo, Perez and Serrano, 2011. Vertebrate microfossil analysis in the palaeontological site of 'Lo Hueco' (Upper Cretaceous, Cuenca, Spain). Journal of Vertebrate Paleontology. Program and Abstracts 2011, 205.
P. sp. (Lopez-Martinez, Canudo, Ardevol, Pereda-Suberbiola, Orue-Etxebarria, Cuenca-Bescos, Ruiz-Omenaca, Muerlaga and Feist, 2001)
Late Maastrichtian, Late Cretaceous
Blasi 2B, Tremp (=Arenisca) Formation, Spain
Material- (MPZ98/76) tooth (2.7x1.5x.6 mm)
(MPZ98/77) tooth (2.8x1.4x.6 mm)
(MPZ98/78) tooth (2.2x1.2x.8 mm)
Comments- These are strongly recurved and have three labial ridges. They were described as unserrated. While MPZ 98-76 is listed as having 15.97 distal serrations per mm by Lopez-Martinez et al. (2001), Torices et al. (2015) list it as serrationless and provide a figure demonstrating this is so. They were listed as cf. Euronychodon sp. by Lopez-Martinez et al., and cf. Paronychodon sp. by Torices et al..
References- Canudo, Lopez Martinez and Ruiz Omenaca, 2001. Los dinosaurios del Maastrichtiense Superior (Cretacico Superior) del pirineo de Huesca (Espana). Actas de Las I Jornadas Internacionales sobre Paleontologia de Dinosaurios y su entorno. 319-328.
Lopez-Martinez, Canudo, Ardevol, Pereda-Suberbiola, Orue-Etxebarria, Cuenca-Bescos, Ruiz-Omenaca, Muerlaga and Feist, 2001. New dinosaur sites correlated with Upper Maastrichtian pelagic deposits in the Spanish Pyrenees: Implications for the dinosaur extinction pattern in Europe. Cretaceous Research. 22, 41-61.
Torices, Currie, Canudo and Pereda-Suberbiola, 2015. Theropod dinosaurs from the Upper Cretaceous of the South Pyrenees Basin of Spain. Acta Palaeontologica Polonica. 60(3), 611-626.
P. sp. (Garcia, Duffaud, Feist, Marandat, Tambareau, Villatte and Sige, 2000)
Turonian-Maastrichtian, Late Cretaceous
La Nueve, Aix, France
Material- (LNE-D01) tooth
Reference- Garcia, Duffaud, Feist, Marandat, Tambareau, Villatte and Sige, 2000. La neuve, gisement a plantes, invertebres et vertebres du Begudien (Senonien superieur continental) du bassin d’Aix-en-Provence. Geodiversitas. 22(3), 326-348.
P? sp. (Sige, Buscalioni, Duffaud, Gayet, Orth, Rage and Sanz, 1997)
Campanian, Late Cretaceous
unnamed unit, Champ-Garimond, Gard, France
Material- teeth
Comments- These differ from most Paronychodon specimens in lacking carinae. They were assigned to Paronychodon by Sige et al. (1997).
Reference- Sige, Buscalioni, Duffaud, Gayet, Orth, Rage and Sanz, 1997. Etat des données sur le gisement Crétacé supérieur continental de Champ-Garimond (Gard, Sud de la France). Munchner Geowiss.. 34, 111-130.
P. sp. nov. (Csiki and Grigorescu, 1998)
Late Maastrichtian, Late Cretaceous
Sinpetru Beds, Romania
Material- (FGGUB R.1431) type A tooth (5.1 mm) (Csiki and Grigorescu, 1998)
(IRSNB coll.) type A tooth (~2.8x~1.1x? mm) (Codrea, Smith, Dica, Folie, Garcia, Godefroit and Van Itterbeecke, 2002)
(IRSNB coll.) teeth (Codrea, Smith, Dica, Folie, Garcia, Godefroit and Van Itterbeecke, 2002)
Comments- FGGUB R.1431 differs from most Paronychodon specimens in having only two lingual grooves and lacking labial grooves. A tooth morphotype photographed by Codrea et al. (2002) is elongate and strongly recurved, "lack serrations on both their mesial and distal carinae, but, contrary to the Paronychodon morphotype, they are not very asymmetrical and their enamel is not ornamented." Csiki and Grigorescu refer FGGUB R.1431 to cf. Euronychodon, while Codrea et al. refer to their teeth as Euronychodon morphotype.
References- Csiki and Grigorescu, 1998. Small theropods from the Late Cretaceous of the Hateg Basin (Western Romania) - an unexpected diversity at the top of the food chain. Oryctos. 1, 87-104.
Codrea, Smith, Dica, Folie, Garcia, Godefroit and Van Itterbeecke, 2002. Dinosaur egg nests, mammals and other vertebrates from a new Maastrichtian site of the Hateg Basin (Romania). Comptes Rendus Palevol. 1(3), 173-180.
P. sp. (Codrea, Smith, Dica, Folie, Garcia, Godefroit and Van Itterbeecke, 2002)
Late Maastrichtian, Late Cretaceous
Sinpetru Beds, Romania
Material- (IRSNB coll.) partial type A tooth (~4.5x~2.4x? mm)
(IRSNB coll.) teeth
Comments- Codea et al. (2002) describe an assemblage collected in 2001. They state "a number of teeth may be identified as theropods on the basis of overall shape, but lack serrations entirely. Some of them closely resemble the Paronychodon morphotype ... in being flat on one side and covered with coarse longitudinal ridges."
Reference- Codrea, Smith, Dica, Folie, Garcia, Godefroit and Van Itterbeecke, 2002. Dinosaur egg nests, mammals and other vertebrates from a new Maastrichtian site of the Hateg Basin (Romania). Comptes Rendus Palevol. 1(3), 173-180.
P. asiaticus (Nessov, 1995) Sues and Averianov, 2013
= Euronychodon asiaticus Nessov, 1995
= "Plesiosaurodon" sp. Nessov vide Sues and Averianov, 2013
Mid-Late Turonian, Late Cretaceous
Bissekty Formation, Uzbekistan
Holotype- (CCMGE N 9/12454) type A tooth
Paratypes- (CCMGE coll.) six teeth
Referred- (ZIN PH 301/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1052/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1053/16) type A tooth (Sues and Averianov, 2013)
(ZIN PH 1054/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1055/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1056/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1057/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1058/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1059/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1060/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1061/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1062/16) premaxillary tooth (Sues and Averianov, 2013)
(ZIN PH 1063/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1064/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1065/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1066/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1067/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1068/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1069/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1070/16) premaxillary tooth (Sues and Averianov, 2013)
(ZIN PH 1072/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1147/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1149/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1150/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1151/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1152/16) type A tooth (Sues and Averianov, 2013)
(ZIN PH 1345/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1833/16) type A tooth (Sues and Averianov, 2013)
Middle Albian-Early Cenomanian, Early-Late Cretaceous
Khodzhakul Formation, Uzbekistan
(ZIN PH 1071/16) type B tooth (Sues and Averianov, 2013)
(ZIN PH 1220/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1221/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1228/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1229/16) tooth (Sues and Averianov, 2013)
(ZIN PH 1230/16) tooth (Sues and Averianov, 2013)
Diagnosis- (after Sues and Averianov, 2013) can differ from P. lacustris in having a higher number of labial ridges (up to 17 versus up to 14).
Comments- These teeth were first described as?Plesiosauria (Nessov, 1985) and Paronychodon cf. lacustris (Nessov, 1986) before being described as a new species of Euronychodon by Nessov (1995). Nessov (1995) distinguished it from Euronychodon portucalensis based on the presence of numerous labial grooves, but the latter are seen in a paratype of E. portucalensis. Sues and Averianov (2013) redescribed the teeth as Paronychodon asiaticus, and noted some specimens were labelled "Plesiosaurodon" by Nessov. Averianov (2007) first announced Paronychodon sp. from the Khodzhakul Formation, which were also described by Sues and Averianov and referred to P. asiaticus.
References- Nessov, 1985. [New mammals of the Cretaceous of the Kyzylkum]. Vyestnik Lyeningradskogo univyersityeta, Biologiya. 17, 8-18.
Nessov, 1986. [The first discovery of the Late Cretaceous bird Ichthyornis in the Old World and some other bones of birds from the Cretaceous and Paleogene of Middle Asia]. Trudy Zoologichyeskogo Instituta AN SSSR. 147, 31-38.
Nessov, 1995. Dinozavri severnoi Yevrazii: Novye dannye o sostave kompleksov, ekologii i paleobiogeografii. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University, St. Petersburg. 156 pp.
Averianov, 2007. Theropod dinosaurs from Late Cretaceous deposits in the northeastern Aral Sea region, Kazakhstan. Cretaceous Research. 28(3), 532-544.
Sues and Averianov, 2013. Enigmatic teeth of small theropod dinosaurs from the Upper Cretaceous (Cenomanian-Turonian) of Uzbekistan. Canadian Journal of Earth Sciences. 50, 306-314.
P? sp. (Averianov, Leshchinskiy, Skutschas, Fayngertz and Rezvyi, 2004)
Aptian-Albian, Early Cretaceous
Ilek (=Shestakovo) Formation, Russia
Material- teeth
Comments- Referred to cf. Paronychodon.
Reference- Averianov, Leshchinskiy, Skutschas, Fayngertz and Rezvyi, 2004. Dinosaurs from the Early Cretaceous Ilek Formations in West Siberia, Russia. 2nd EAVP Meeting. July 19-24, 2004. Brno, Czech Republic. Abstracts of papers and posters with program, Excursion Guidebook. pg 6.

unnamed possible Troodontidae (Antunes and Sigogneau-Russell, 1992)
Maastrichtian, Late Cretaceous
Unnamed unit, Distrito do Coimbra, Portugal
Material- (AV 7) fragmentary tooth
(TV 43) fragmentary tooth
(TV 52) fragmentary tooth
Reference- Antunes and Sigogneau-Russell, 1992. La Faune de Petits Dinosaures du Cretace Terminal Portugais. Comunicações dos Serciços geolögicos de Portugal. 78(1), 49-62.

unnamed troodontid (Averianov, 2016)
Santonian, Late Cretaceous
Bostobe Formation, Kazakhstan
Material- (ZIN PH 45/49) partial frontal
Reference- Averianov, 2016 (online 2015). Frontal bones of non-avian theropod dinosaurs from the Upper Cretaceous (Santonian-?Campanian) Bostobe Formation of the northeastern Aral Sea region, Kazakhstan. Canadian Journal of Earth Sciences. 53(2). 168-175.

undescribed troodontid (Suzuki and Watabe, 2000)
Cenomanian-Santonian, Late Cretaceous
Bayshin Tsav, Baynshire Formation, Mongolia
Material- (IGM coll.; 950728 BTs-Nar or 950728 BTs Theropod) partial skeleton including six dorsal vertebrae, several dorsal ribs, gastralia, seven sacral or proximal caudal vertebrae, manual ungual I, phalanx II-2, manual ungual II, phalanx III-1, phalanx III-2, manual claw sheath, manual phalanges, manual ungual, manual claw sheath, pubis, incomplete femur, tibia, fibula, pedal phalanges, pedal ungual, fragments
Comments- This specimen was found on July 28 1995, listed as "A skeleton of small theropod discovered near Bayshin Tsav IV" and "Small theropod skeleton" by Suzuki and Watabe (2000). They photographed it as "manus of small theropod at Bayshin Tsav". Tsogtbaatar (2004) states it was prepared in 2000 (as 950728 BTs-Nar) and identified as a troodontid, being stored at the IGM.
Reference- Suzuki and Watabe, 2000. Report on the Japan - Mongolia Joint Paleontological Expedition to the Gobi desert, 1995. Hayashibara Museum of Natural Sciences Research Bulletin. 1, 45-57.
Tsogtbaatar, 2004. Fossil specimens prepared in Mongolian Paleontological Center 1993-2001. Hayashibara Museum of Natural Sciences Research Bulletin. 2, 123-128.

undescribed possible troodontid (Norton, DML 2000)
Late Campanian, Late Cretaceous
Ukhaa Tolgod, Djadochta Formation, Mongolia
Material- (IGM 97/155) specimen including manual phalanx III-3
Comments- Norton (DML, 2000) noted this specimen was on display at the AMNH Fighting Dinosaurs exhibit. Discovered in 1997 at Ukhaa Tolgod, it was said to be "unpublished but noted as having "raptor like " traits". Prieto-Marquez et al. (2011) state "troodontid specimen MAE 97-155" has a manual phalanx III-3 identical to halszkaraptorine ISMD-VP09.
References- Norton, DML 2000. https://web.archive.org/web/20210603191138/http://dml.cmnh.org/2000Jun/msg00082.html
Prieto-Marquez, Bolortsetseg and Horner, 2011. A diminutive deinonychosaur (Dinosauria: Theropoda) from the Early Cretaceous of Oosh (Ovorkhangai, Mongolia). Alcheringa. 1-20.

unnamed possible troodontid (Dong, 1997)
Early Albian, Early Cretaceous
Upper Gray Beds of the Zhonggou Formation, Gansu, China
Material- (IVPP V11119) two teeth, two caudal vertebrae, partial tibia, distal tarsal, incomplete metatarsal II, phalanx II-1 (17 mm), phalanx II-2 (13 mm), pedal ungual II (9 mm), distal metatarsal III, phalanx III-1, partial metatarsal IV, phalanx IV-1
Comments- Dong (1997) referred this to Sinornithoides sp. nov. based on undescribed distal tarsal similarities, subequal size, and the plesiomorphically limited proximal extent of the distal articular surface on metatarsal III. However, he notes the less robust metatarsal IV differs. This suggests the specimen was outside the Sinornithoides+Troodon clade and should not be referred to the former genus. Hartman et al. (2019) recovered this as a coelurosaur outside several clades including Troodontidae+Dromaeosauridae.
References- Dong, 1997. On small theropods from Mazongshan area, Gansu province, China. In Dong (ed.). Sino-Japanese Silk Road Dinosaur Expedition. China Ocean Press. 13-18.
You, Morschhauser, Li and Dodson, 2018. Introducing the Mazongshan dinosaur fauna. Journal of Vertebrate Paleontology. 38(supp. 1), 1-11.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

undescribed troodontid (Kobayashi, Lu, Lee, Xu and Zhang, 2008)
Late Cretaceous
Qiupa Formation, Henan, China
Material- skeleton
Comments- Kobayashi et al. (2008) state "A new locality, yielded Luanchuanraptor, in Tantou Basin in Luanchuan County exposes the Upper Cretaceous Qiupa Formation and is rich in dinosaur eggs and bones, such as undescribed skeletons of an ... troodontid." Note this is not the subsequently described Xixiasaurus, which is from the Majiacun Formation in Xixia County near Songgou village, not the Qiupa Formation in Luanchuan County near Qiupa village.
Reference- Kobayashi, Lu, Lee, Xu and Zhang, 2008. A new basal ornithomimid (Dinosauria: Theropoda) from the Late Cretaceous in Henan province of China. Journal of Vertebrate Paleontology. 28(3), 101A.

Troodontinae sensu Hendrickx, Mateus, Araújo and Choiniere, 2019
Definition- (Sinovenator changii + Troodon formosus)
Reference- Hendrickx, Mateus, Araújo and Choiniere, 2019. The distribution of dental features in non-avian theropod dinosaurs: Taxonomic potential, degree of homoplasy, and major evolutionary trends. Palaeontologia Electronica. 22.3.74, 1-110.

Sinovenatorinae Shen, Lu, Liu, Kundrát, Brusatte and Gao, 2017
Definition- (Sinovenator changii <- Jinfengopteryx elegans, Troodon formosus, Passer domesticus) (Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019)
Other definitions- (Sinovenator changii <- Troodon formosus, Saurornithoides mongoliensis, Anchiornis huxleyi, Archaeopteryx lithographica, Gallus gallus, Unenlagia comahuensis, Dromaeosaurus albertensis) (Shen, Lu, Liu, Kundrát, Brusatte and Gao, 2017)
Comments- This clade was recovered by Shen et al. (2017) using Brusatte's version of the TWiG analysis. In their topology it includes Sinovenator, Mei, Daliansaurus and Sinusonasus. Hartman et al. (2019) redefined this clade to exclude Jinfengopteryx, previously given its own subfamily.
References- Shen, Lu, Liu, Kundrát, Brusatte and Gao, 2017. A new troodontid dinosaur from the Lower Cretaceous Yixian Formation of Liaoning Province, China. Acta Geologica Sinica. 91(3), 763-780.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Mei Xu and Norell, 2004
M. long Xu and Norell, 2004
Early Aptian, Early Cretaceous
Lujiatun Beds of Yixian Formation, Liaoning, China
Holotype- (IVPP V12733; ?= IVPP V12744 of Xu et al. 2014) (530 mm; subadult) incomplete skull (53 mm), sclerotic plates, incomplete mandible (56 mm), ten cervical vertebrae (67 mm), dorsal vertebrae (92 mm), dorsal ribs, gastralia, sacrum (30 mm), caudal vertebrae (257 mm), chevrons, scapulae (45 mm), coracoids (11 mm), furcula, sternal rib fragments(?), humeri (42 mm), radii (39 mm), ulnae (42 mm), semilunate carpal, (manus 67 mm) metacarpal I, phalanx I-1, manual ungual I, metacarpal II, phalanx II-1, phalanx II-2, manual ungual II, phalanx III-2, phalanx III-3, manual ungual III, ilia, pubes, ischium, femora (81 mm), tibiae (106 mm), fibula, astragali, distal tarsals, metatarsal I, phalanx I-1, pedal ungual I, metatarsal II (51 mm), phalanx II-1, phalanx II-2, pedal ungual II, metatarsal III (58 mm), phalanx III-1, phalanx III-2, phalanx III-3, pedal ungual III, metatarsal IV (55 mm), phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV, metatarsal V
Referred- (DNHM D2514) (~325 mm; ~420 g; adult) incomplete skull (~49 mm), mandible, fragmentary fourth cervical vertebra, fifth cervical vertebra, sixth cervical vertebra, seventh cervical vertebra, eighth cervical vertebra, ninth cervical vertebra, tenth cervical vertebra, incomplete eleventh cervical vertebra, cervical ribs, first dorsal neural arch, second dorsal neural arch, third dorsal neural arch, fourth dorsal neural arch, fifth dorsal neural arch, incomplete eighth dorsal vertebra, incomplete ninth dorsal vertebra (5.8 mm), incomplete tenth dorsal vertebra (6 mm), incomplete eleventh dorsal vertebra (5.9 mm), incomplete twelfth dorsal vertebra (5.9 mm), incomplete thirteenth dorsal vertebra, dorsal rib fragments, sacrum (22.2 mm), first caudal vertebra, second caudal vertebra, third caudal vertebra, fourth caudal vertebra (4 mm), fifth caudal vertebra (4 mm), sixth caudal vertebra (4.3 mm), seventh caudal vertebra (4.9 mm), eighth caudal vertebra (5.5 mm), ninth caudal vertebra (8 mm), tenth caudal vertebra (10.3 mm), eleventh caudal vertebra (11.1 mm), twelfth caudal vertebra (11 mm), thirteenth caudal vertebra (11.2 mm), fourteenth caudal vertebra (10.9 mm), fifteenth caudal vertebra (10.9 mm), sixteenth caudal vertebra (10.6 mm), seventeenth caudal vertebra (10.6 mm), eighteenth caudal vertebra, eleven chevrons, scapulae (36, 40 mm), coracoid, humeri (36 mm), radii (one incomplete), ulnae (one incomplete; ~34 mm), metacarpal I (4 mm), phalanx I-1 (14 mm), manual ungual I (7.3 mm), metacarpal II (13 mm), phalanx II-1 (7.8 mm), phalanx II-2 (13 mm), manual ungual II, metacarpal III (14.3 mm), phalanx III-1 (8.1 mm), phalanx III-2 (8.1 mm), phalanx III-3 (10.7 mm), ilia (34.4 mm), proximal pubes, femora (~65 mm), tibiotarsi (~86.1 mm), fibulae, distal metatarsal II (~42.5 mm), phalanx II-2, pedal ungual II, distal metatarsal III (~49 mm), phalanx III-1 (12.8 mm), phalanx III-3, metatarsals IV (one distal; 45.7 mm), phalanx IV-1 (8.4 mm), phalanx IV-2 (6.4 mm), phalanx IV-3 (5.9 mm), phalanx IV-4 (5.2 mm), metatarsal V (11 mm) (Gao et al., 2012)
Diagnosis- (after Xu and Norell, 2004) extremely large external nares extending posteriorly over one half of the maxillary tooth row; closely packed middle maxillary teeth; maxillary tooth row extending posteriorly to the level of the preorbital bar; robust U-shaped furcula; most proximal end of the pubic shaft is significantly compressed anteroposteriorly, and extends laterally just ventral to the articulation with the ilium; lateral process on distal tarsal IV.
(after Gao et al., 2012) posterior sacrum extremely wide with elongate fourth and fifth transverse processes; ilium strongly sigmoid in dorsal view, with a stronger lateral curve than in Velociraptor or Anchiornis.
Comments- The holotype was discovered prior to April 2004.
References- Xu and Norell, 2004. A new troodontid dinosaur from China with avian-like sleeping posture. Nature. 431, 838-841.
Gao, Morschhauser, Varricchio, Liu and Zhao, 2012. A second soundly sleeping dragon: New anatomical details of the Chinese troodontid Mei long with implications for phylogeny and taphonomy. PLoS ONE. 7(9), e45203.
Xu, Han and Zhao, 2014. Homologies and homeotic transformation of the theropod 'semilunate' carpal. Nature Scientific Reports. 4, 6042.

Xiaotingia Xu, You, Du and Han, 2011
X. zhengi Xu, You, Du and Han, 2011
Oxfordian, Late Jurassic
Tiaojishan Formation?, Liaoning, China
Holotype- (STM 27-2) (820 g adult) skull (~61 mm to quadrate), mandible (62 mm), (cervical series 80 mm) ten cervical vertebrae, cervical ribs, (dorsal series 118 mm) thirteen dorsal vertebrae, dorsal ribs, gastralia, synsacrum, three proximal caudal vertebrae, scapulae (55 mm), partial coracoid, furcula (42 mm across), humeri (71 mm), radii (63 mm), ulnae (65 mm), semilunate carpal, metacarpal I (10 mm), phalanges I-1 (21 mm), manual unguals I (14 mm), metacarpals II (24 mm), phalanges II-1 (15 mm), phalanges II-2 (25 mm), manual unguals II (14 mm), metacarpals III (24 mm), phalanges III-1 (8 mm), phalanges III-2 (4 mm), phalanges III-3 (15 mm), manual ungual III (11 mm), manual claw sheaths, ilia (52 mm), partial pubis, incomplete ischium (~28 mm), incomplete femora (~84 mm), incomplete tibia, incomplete fibula, metatarsal I (9 mm), phalanx I-1 (6 mm), pedal ungual I (6 mm), distal metatarsal II, phalanx II-1 (12 mm), phalanx II-2 (9 mm), pedal ungual II (13 mm), distal metatarsal III, phalanx III-1 (17 mm), phalanx III-2 (13 mm), phalanx III-3, pedal ungual III, distal metatarsal IV, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV, pedal claw sheaths, feathers
Diagnosis- (after Xu et al., 2011) maxillary posterior ramus has depth at mid-length exceeding that of dentary; surangular has little lateral exposure and forms a wide, flat dorsal surface over posterior part of mandible; extremely large surangular foramen >6% of mandibular length; posterior end of mandible blunt and dorsoventrally expanded; proximalmost caudal centra less than half as long as posterior dorsal centra; metacarpal III more robust than metacarpals I and II; manual phalanx II-2 longer than metacarpal II.
Comments- As the holotype was acquired from a dealer with no quarry information (prior to November 2010), Xiaotingia may instead be from the Yixian Formation which outcrops in the same area. Xu et al. (2011) used a version of Senter's TWiG matrix to place Xiaotingia in Archaeopterygidae with Archaeopteryx and Anchiornis, with the family in basal Deinonychosauria. More recently, Hartman et al. (2019) used a far more extensive TWiG analysis to recover it as a sinovenatorine troodontid. As they state, "troodontid characters present in Xiaotingia but not anchiornithines include distally positioned obturator process (183:2), and characters shared with sinovenatorines include large posterior surangular foramen (80:2), capital groove in humerus (458:1), metacarpal III extending distally past metacarpal II (640:1), laterally ridged ischium (182:2), and enlarged pedal ungual II (224:1). Forcing Xiaotingia into Archaeopterygidae requires nine more steps, which strongly suggests it is not a member considering we included all of the TWiG data originally used to place it there. Alternative placements as a non-anchiornithine avialan (Lee et al., 2014), a dromaeosaurid (Senter et al., 2012), and a scansoriopterygid relative (Lefèvre et al., 2017) are eight, five, and 26 more steps, respectively."
References- Xu, You, Du and Han, 2011. An Archaeopteryx-like theropod from China and the origin of Avialae. Nature. 475, 465-470.
Senter, Kirkland, DeBlieux, Madsen and Toth, 2012. New dromaeosaurids (Dinosauria: Theropoda) from the Lower Cretaceous of Utah, and the evolution of the dromaeosaurid tail. PLoS ONE. 7(5), e36790.
Lee, Cau, Naish and Dyke, 2014. Sustained miniaturization and anatomical innovation in the dinosaurian ancestors of birds. Science. 345(6196), 562-566.
Lefèvre, Cau, Cincotta, Hu, Chinsamy, Escuillié and Godefroit, 2017. A new Jurassic theropod from China documents a transitional step in the macrostructure of feathers. The Science of Nature. 104:74.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Jianianhualong Xu, Currie, Pittman, Xing, Meng, Lu, Hu and Yu, 2017
J. tengi Xu, Currie, Pittman, Xing, Meng, Lu, Hu and Yu, 2017
Late Barremian-Early Aptian, Early Cretaceous
Yixian Formation, Liaoning, China
Holotype- (DLXH 1218) (~1.12 m; ~2.4 kg; adult) skull, sclerotic plates, mandibles, hyoids, cervical series (~160 mm) mostly fused to cervical ribs (except c3 and c6), dorsal vertebrae (~170 mm), nine pairs of dorsal ribs, ~12 rows of gastralia, sacrum, first to twenty-third caudal vertebrae (~540 mm), chevrons, partial scapulae, coracoid, furcula, humeri, radii, ulnae, scapholunare, semilunate carpal, distal carpal III, metacarpals I, phalanges I-1, manual unguals I, metacarpals II, phalanges II-1, phalanges II-2, manual unguals II, metacarpals III, phalanges III-1, phalanges III-2, phalanges III-3, manual unguals III, manual claw sheaths, ilia (one fragmentary), pubes, ischia, femora, distal tibiae, distal fibula, fragmentary proximal tarsals, metatarsal I, phalanges I-1, pedal unguals I, distal tarsals III, distal tarsals IV, metatarsals II, phalanx II-1, phalanx II-2, pedal ungual II, metatarsals III, metatarsals IV, phalanx IV-1, pedal phalangeal fragments, metatarsals V, body feathers (30-~75 mm), remiges, retrices (~120 mm)
Diagnosis- (after Xu et al., 2017) maxillary anterior ramus triangular and relatively tall; maxillary ascending process extending posterodorsally at a high angle (an angle of ~45 degrees to maxillary ventral margin); long manual phalanx I-1 (slightly shorter than metacarpal II) with prominent proximoventral heel, large groove along the medial surface of more than proximal half; highly elongated manual phalanx II-2 (slightly longer than metacarpal II); ilium with slightly concave dorsal margin in lateral view; metatarsal IV without prominent ventral flange.
Comments- The holotype was discovered prior to Novemver 2016. Xu et al. recovered it closer to troodontines than Sinovenator using Senter's version of the TWiG matrix, but Hartman et al. (2019) incorporating more TWiG data found it to be a sinovenatorine instead. Only a single step moves it closer to troodontines however.
References- Xu, Currie, Pittman, Xing, Meng, Lu, Hu and Yu, 2017. Mosaic evolution in an asymmetrically feathered troodontid dinosaur with transitional features. Nature Communications. 8:14972.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

unnamed troodontid (Tsuihiji, Watabe, Barsbold, Suzuki and Tsogtbaatar, 2009)
Barremian-Albian?, Early Cretaceous
Khamaryn Ar, Mongolia
Material- (IGM 100/140; 080924 KhA OTGON) thirteen distal caudal vertebrae, five distal chevrons, distal radius, distal ulna, scapholunare, semilunate carpal, metacarpal I (13.9 mm), phalanx I-1 (30.7 mm), manual ungual I (20.4 mm), metacarpals II (one incomplete, one distal), phalanges II-1 (18.8 mm), phalanges II-2 (30.1, 30.7 mm), manual unguals II (22.9, 23.2 mm), metacarpals III (one incomplete, one distal), phalanges III-1 (7.2 mm), phalanges III-2 (9.2 mm), phalanges III-3 (19.1 mm), manual unguals III (18.5 mm), manual claw sheaths, phalanx I-1 (11.5 mm), pedal ungual I (12 mm), partial metatarsal II, phalanx II-1 (20.4 mm), phalanx II-2 (14.9 mm), incomplete pedal ungual II, partial metastarsal III, phalanx III-1 (25.6 mm), phalanx III-2 (18 mm), phalanx III-3 (16.9 mm), incomplete pedal ungual III, incomplete metatarsal IV, phalanx IV-1 (16.8 mm), phalanx IV-2 (15.1 mm), phalanx IV-4 (13.7 mm), incomplete pedal ungual IV
Comments- IGM 100/140 was discovered on September 23-25 2008 (Tsubamoto et al., 2010), given the field number 080924 KhA OTGON and photographed and mentioned by Tsubamoto et al. as "Dromaeosauridae or Troodontidae" (fig. 9B). Tsuihiji et al. (2009) mention it in an abstract, but it wasn't fully described until Tsuihiji et al. (2015). This specimen was added to a version of Senter's TWiG analysis by Tsuihiji et al. (2015) and found to be more derived than Byronosaurus. Hartman et al. (2019) included it in their more extensive TWiG analysis and recovered it as a sinovenatorine sister to Jianianhualong, but only a single step moves it closer to troodontines.
References- Tsuihiji, Watabe, Barsbold, Suzuki and Tsogtbaatar, 2009. New material of a troodontid theropod (Dinosauria: Saurischia) from the Lower Cretaceous of Mongolia. 4th International Symposium of IGCP 507, Abstracts. 59.
Tsubamoto, Saneyoshi, Tsogtbaatar, Chinzorig, Khatanbaatar, Mainbayar and Suzuki, 2010. Report of the HMNS-MPC Joint Paleontological Expedition in 2008. Hayashibara Museum of Natural Sciences Research Bulletin. 3, 29-39.
Tsuihiji, Barsbold, Watabe, Tsogtbaatar, Suzuki and Hattori, 2015. New material of a troodontid theropod (Dinosauria: Saurischia) from the Lower Cretaceous of Mongolia. Historical Biology. 28(1-2), 128-138.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Sinovenator Xu, Norell, Wang, Makovicky and Wu, 2002
S. changii Xu, Norell, Wang, Makovicky and Wu, 2002
Early Aptian, Early Cretaceous
Lujiatun Beds of Yixian Formation, Liaoning, China
Holotype- (IVPP V12615) (adult) incomplete skull (~90 mm), dentary, supradentary, surangulars, anterior cervical vertebra, mid cervical vertebra, mid cervical vertebra, posterior cervical vertebra, third dorsal vertebra (9.8 mm), fourth dorsal vertebra (9.8 mm), fifth dorsal vertebra (10 mm), sixth dorsal vertebra (10.2 mm), seventh dorsal vertebra (10.9 mm), eighth dorsal vertebra (11.2 mm), ninth dorsal vertebra (11.6 mm), tenth dorsal vertebra (11.7 mm), eleventh dorsal vertebra (11.3 mm), twelfth dorsal vertebra, fragmentary thirteenth dorsal vertebra, two partial dorsal ribs, sacrum, first caudal vertebra (7.2 mm), second caudal vertebra (8 mm), third caudal vertebra (10 mm), fourth caudal vertebra (10 mm), fifth caudal vertebra (10.2 mm), sixth caudal vertebra (~10.2 mm), incomplete scapula (~66 mm), coracoid, distal humerus, partial radius, partial ulna, metacarpal, manual ungual, ilium (~60 mm), pubes (97, 94 mm), ischium (40 mm), femur (117.5 mm), tibia (152.9 mm), incomplete fibulae, astragalus, metatarsal I (~19 mm), metatarsal II (77 mm), phalanx II-2, pedal ungual II, metatarsal III (86.2 mm), metatarsals IV (82.6, 83.4 mm), partial metatarsal V
Paratype- (IVPP V12583) (subadult) sacrum, first caudal vertebra (7 mm), second caudal vertebra (8.2 mm), third caudal vertebra (8 mm), fourth caudal vertebra (8 mm), fifth caudal vertebra (8 mm), sixth caudal vertebra (8 mm), seventh caudal vertebra (8.6 mm), eighth caudal vertebra (10 mm), ninth caudal vertebra (10.9 mm), tenth caudal vertebra (14.5 mm), eleventh caudal vertebra (16.1 mm), twelfth caudal vertebra (19 mm), thirteenth caudal vertebra, fourteenth caudal vertebra (18 mm), fifteenth caudal vertebra (18 mm), sixteenth caudal vertebra (20 mm), seventeenth caudal vertebra (19 mm), eighteenth caudal vertebra (18 mm), nineteenth caudal vertebra (17.9 mm), twentieth caudal vertebra (17.5 mm), twenty-first caudal vertebra (17.2 mm), twenty-second caudal vertebra (17.9 mm), twenty-third caudal vertebra (19 mm), twenty-fourth caudal vertebra (19 mm), twenty-fifth caudal vertebra (18.5 mm), twenty-sixth caudal vertebra (17.5 mm), proximal scapulae, fragmentary coracoids, humeri (71 mm), radius (~87 mm), ulna (91 mm), semilunate carpal, distal carpal III, metacarpal I (12 mm), phalanx I-1 (28 mm), metacarpal II (28.5 mm), two manual phalanges, pubis (87 mm), ischium (42.5 mm), femur (105 mm), tibiotarsi (148, 146 mm), fibulae, metatarsal II (79 mm), phalanges II-1 (15, 15 mm), phalanges II-2 (10, 10 mm), metatarsal III (91.7 mm), phalanges III-1 (21.5, 22 mm), phalanx III-2 (14.6 mm), phalanx III-3 (~13.5 mm), metatarsal IV (88 mm), phalanges IV-1 (15, 14.7 mm), phalanges IV-2 (12, 12.8 mm), phalanx IV-3 (10.2 mm), phalanx IV-4 (10.2 mm), partial metatarsal V
Referred- (IVPP V14009) (adult) specimen including semilunate carpal, metacarpal I, metacarpal II and metacarpal III (Xu et al., 2014)
(IVPP V14322) mandible, cervical vertebrae, dorsal vertebrae, dorsal ribs, proximal humerus, manual phalanges, manual unguals, pubis, ischium, femora, tibiae, partial fibula, astragalus, calcaneum, metatarsal II, phalanx II-1, phalanx II-2, pedal ungual II, metatarsal III, phalanx III-1, phalanx III-2, metatarsal IV, phalanx IV-1, phalanx IV-2 (Manabe, 2005)
(IVPP coll.) femur (206 mm), tibia (147 mm), metatarsal II, phalanx II-1, phalanx II-2, metatarsal III (92 mm), phalanx III-1, phalanx III-2, phalanx III-3 metatarsal IV, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV (White, 2009)
(PMOL-AD00102) (adult) posterior skull (~161 mm), stapes, posterior mandibles, proatlases, atlantal intercentrum, atlantal neural arches, atlantal ribs, axis, axial ribs, incomplete third cervical vertebra, incomplete third cervical vertebra, incomplete third cervical vertebra, sixth cervical prezygapophyses, partial cervical ribs (Yin et al., 2018)
? skull, cervical vertebrae, dorsal ribs, sacral vertebrae, caudal vertebrae, scapula, humerus, radius, ulna, manus, ilia, femur, tibiae, fibula, pes (Fossil Mall, online 2015)
Diagnosis- (after Xu et al., 2002) straight and vertical anterior margin of antorbital fenestra (also in Sinusonasus); surangular T-shaped in cross-section; prominent lateral cnemial crest continuous with the fibular crest.
(after Yin et al., 2018) well-developed medial shelf on jugal; slender bar in parasphenoid recess; lateral groove on pterygoid flange of ectopterygoid; lateral surface of anterior cervical vertebrae bearing two pneumatic foramina.
Other diagnoses- Xu et al. (2002) proposed a frontal with a vertical lamina bordering the lacrimal as diagnostic, but while present in the holotype this is missing in PMOL-AD00102 (Yin et al., 2018).
Comments- Creisler (DML 2002) noted Sinovenator changii was named after a woman, so suggested it be emended to S. changiae. Similarly, Xu (2002) states Li indicated it should be S. changae, which is used in that thesis. However, the Fourth Edition of the ICZN no longer requires emendations based on this reasoning (Article 31.1.3- "The original spelling of a name formed under Articles 31.1.1 and 31.1.2 is to be preserved [Art. 32.2] unless it is incorrect [Arts. 32.3, 32.4]"), with Article 32.3 saying "The correct original spelling of a name is to be preserved unaltered, except where it is mandatory to change the suffix or the gender ending under Article 34" where Article 34 involves matching genus and species genders, and Article 32.4 saying "An original spelling is an "incorrect original spelling" if it must be corrected as required in Article 32.5" and Article 32.5 saying " Incorrect transliteration or latinization ... are not to be considered inadvertent errors". If Sinovenator "changiae" was published by Haubold (2003) while S. "changae" was published by Long and Schouten (2008), but ICZN Article 32.2.3 states both are available names with their own authorships, though objective junior synonyms of S. changii.
The holotype and paratype were discovered in Summer 2001 (Xu, 2002) and named and briefly described by Xu et al. (2002). A more detailed description is in Xu's (2002) thesis, but has not yet been published.
Senter (2007) mentioned an undescribed specimen whose photo was available on www.dinosaur.net.cn (2004). This is IVPP V14322, and is illustrated in Manabe (2005).
White (2009) describes and illustrates the pes of an unregistered specimen at the IVPP as Sinovenator sp.
An undescribed basically complete specimen is referred to Sinovenator on the Fossil Mall website (2015), but may be at least partially faked due to its apparent lumbar region and non-maniraptoran forelimb position.
Yin et al. (2018) described a posterior skull of a new specimen (PMOL-AD00102) that differs from the smaller holotype in a few characters- frontal without vertical lamina bordering the lacrimal; presence of a septum between the basal tubera; presence of a basisphenoid recess; deep sagittal crest; basipterygoid process with a blunt distal end. They considered these possibly ontogenetic or taphonomic.
Senter et al. (2004) corrected Xu et al.'s description of several characters, finding the teeth to be unserrated, the antorbital fossa to lack a prominent rim, the anterior and posterior dentary teeth to be subequal in size and density, and the fourth metatarsal to be subequal in diameter to the second. Senter (2007) later corrected his account of dentary tooth density, agreeing with Xu et al. that the anterior teeth were more densely packed.
References- Creisler, DML 2002. https://web.archive.org/web/20210121093206/http://dml.cmnh.org/2002Feb/msg00579.html
Xu, 2002. Deinonychosaurian fossils from the Jehol Group of western Liaoning and the coelurosaurian evolution. PhD Thesis. Chinese Academy of Sciences. 325 pp.
Xu, Norell, Wang, Makovicky and Wu, 2002. A basal troodontid from the Early Cretaceous of China. Nature. 415, 780-784.
Haubold, 2003. Literaturbericht - Dinosauria 2002-2003. Zentralblatt für Geologie und Paläontologie, Teil II. 2003(5/6), 467-524.
Dinosaur.net, online 2004. http://www.dinosaur.net.cn/_Kyohaku2004/show_fly.htm (not archived but but copied at http://projectos.cienciaviva.pt/pw011/jazidas/220[1].sinevenator.jpg)
Senter, Barsbold, Britt and Burnham, 2004. Systematics and evolution of Dromaeosauridae. Bulletin of Gunma Natural History Museum. 8, 1-20.
Manabe, 2005. The Dinosaur Expo 2005: Evolution of Dinosaurs from their Origin to Birds. Asahi Shinbunsha. 149 pp.
Senter, 2007. A new look at the phylogeny of Coelurosauria. Journal of Systematic Palaeontology. 5(4), 329-463.
Long and Schouten, 2008. Feathered Dinosaurs: The Origin of Birds. Oxford University Press. 193 pp.
White, 2009. The subarctometatarsus: Intermediate metatarsus architecture demonstrating the evolution of the arctometatarsus and advanced agility in theropod dinosaurs. Alcheringa. 33(1), 1-21.
Xu, Han and Zhao, 2014. Homologies and homeotic transformation of the theropod 'semilunate' carpal. Nature Scientific Reports. 4, 6042.
Fossil Mall, online 2015. http://www.fossilmall.com/Science/Sites/China/Sinovenator/Sinovenator.jpg
Ma and Rayfield, 2015. Reconstructing the cranial musculoskeletal anatomy of two maniraptoran theropod dinosaurs and implications for avian evolution. Journal of Vertebrate Paleontology. Program and Abstracts 2015, 170.
Yin, Pei and Zhou, 2018. Cranial morphology of Sinovenator changii (Theropoda: Troodontidae) on the new material from the Yixian Formation of western Liaoning, China. PeerJ. 6:e4977.

Liaoningvenator Shen, Zhao, Gao, Lu and Kundrát, 2017
L. curriei Shen, Zhao, Gao, Lu and Kundrát, 2017
Early Aptian, Early Cretaceous
Lujiatun Beds of Yixian Formation, Liaoning, China
Holotype- (DNHM D3012) (4+ year old subadult) skull (97.6 mm), mandibles, ten cervical vertebrae fused to cervical ribs (series ~138 mm; c3-8 13.6-16.1 mm [c5], c9 12.5, c10 12.1 mm), twelve dorsal vertebrae (series ~150 mm), several partial to incomplete dorsal ribs, gastralia, sacrum, first to sixteenth caudal vertebrae (series ~245 mm; c14 18.9 mm), chevron?, incomplete scapula (~59 mm), coracoids, humerus (~65 mm), radii (one distal), ulnae (one distal), phalanx I-1 (32.6 mm), manual ungual I, partial metacarpal II, phalanx II-1 (26.3 mm), phalanges II-2 (one distal; ~34 mm), manual unguals II, partial metacarpal III, partial phalanx III-1, phalanx III-2, phalanx III-3, manual ungual III, ilia (71, 77 mm), partial pubis, distal ischia, femora (one partial; 111 mm), tibiotarsi (162, ~152 mm), fibula (152 mm), distal tarsal III, distal tarsal IV, phalanx I-1, pedal ungual I, metatarsals II (~82 mm), phalanx II-1, phalanx II-2, partial pedal ungual II, metatarsals III (~93 mm), phalanx III-1, phalanx III-2, phalanx III-3, metatarsal IV, phalanx IV-1, metatarsal V (~24 mm)
Referred- ?(CAGS-IG01-004) incomplete skeleton including skull (Hwang et al., 2004)
Diagnosis- (after Shen et al., 2017) prominent slender triradiate postorbital; transition point in caudal series starts from seventh caudal vertebra; deltopectoral crest distinctly extended to distal half of humeral shaft; manual phalanx I-1 longer than metacarpal II, ratio about 1.49; no posterodistal process on ischium; slender obturator process on ischium; metatarsus width distally distinctly decreases.
Comments- Shen et al. (2017) added Liaoningvenator to a version of Senter's TWiG analysis and recovered it sister to Eosinopteryx as an anchiornithine troodontid. Hartman et al. (2019) found it to be sister to IGM 100/1126, closer to troodontines than Anchiornis or sinovenatorines. Wwang et al. (2004) mentioned CAGS-IG01-004 as a specimen from the Lujiatun as being similar to Almas, so this may be a second individual of Liaoningvenator. It was stated to have small teeth with constricted bases and carinae lacking serrations, an apparently absent postorbital (may be taphonomic), and no quadratojugal-squamosal contact.
Based on figures, I believe when Shen et al. state "The manual phalanx III-1 is the longest", they meant phalanx II-2.
References- Hwang, Norell, Ji and Gao, 2004. A new troodontid from the lower Yixian Formation of China and its affinities to Mongolian troodontids. Journal of Vertebrate Paleontology. 24(3), 26A.
Shen, Zhao, Gao, Lu and Kundrát, 2017. A new troodontid dinosaur (Liaoningvenator curriei gen. et sp. nov.) from the Early Cretaceous Yixian Formation in western Liaoning Province. Acta Geoscientica Sinica. 38(3), 359-371.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

unnamed troodontid (Wang, Zhang, Tan, Jiangzuo, Zhang and Tan, 2021 online)
Late Campanian, Late Cretaceous
Wulansuhai Formation, Inner Mongolia, China
Material- (LH PV39) (adult) ~fourth cervical vertebra (20.51 mm), ~fifth cervical vertebra (20.82 mm), ~sixth cervical vertebra (19.37 mm), ~seventh cervical fragment, ~eighth cervical vertebra (15.95 mm), ~ninth cervical vertebra (14.18 mm), synsacrum (10.70, 9.80, 7.25, 7.53, 8.49 mm), four mid caudal vertebrae (23.12, 25.88, 24.81, 26.22 mm), two fragmentary chevrons, manual ungual I (24.2 mm on curve), fragmentary manual ungual
Comments- This was discovered in 2001 and first reported by Sereno (online 2001) with photos of two cervicals and an ungual, misidentified as a dromaeosaur. Wang et al. (2021) described it in detail, recovering it as the most basal sinovenatorine using Pei's version of the TWiG analysis in a parsimony analysis, and in a more derived position in a polytomy with Almas, IGM 100/1126, Talos and troodontids closer to troodontines in a Bayesian analysis. Adding it to Hartman et al.'s maniraptoromorph matrix results in a position sister to Liaoningvenator, then IGM 100/1126. Forcing it to be a sinovenatorine or slightly closer to Troodontinae sister to the contemporaneous and also small Philovenator both take a single additional step, suggesting its position within Troodontidae is not strongly resolved and that it may belong to Philovenator.
References- Sereno, online 2001. https://web.archive.org/web/20020603194101/http://www.projectexploration.org/mongolia/u52701.htm
Wang, Zhang, Tan, Jiangzuo, Zhang and Tan, 2021 online. New troodontid theropod specimen from Inner Mongolia, China clarifies phylogenetic relationships of later-diverging small-bodied troodontids and paravian body size evolution. Cladistics. Early View. 10.1111/cla.12467

undescribed troodontid (Dufeau, 2003)
Late Campanian, Late Cretaceous
Zos Wash, Djadokhta Formation, Mongolia
Material- (IGM 100/1126; = IGM 100/1005, IGM 100/1128) (6+ year old adult) incomplete skull (78.2 mm), sclerotic plates, mandibles (68.1, 66.3 mm), hyoids, synsacrum, first caudal vertebra, second caudal vertebra (6.1 mm), third caudal vertebra (6.8 mm), fourth caudal vertebra (7.2 mm), fifth caudal vertebra (8.2 mm), sixth caudal vertebra (8.8 mm), seventh caudal vertebra (8.9 mm), eighth caudal vertebra (9.5 mm), ninth caudal vertebra (9.9 mm), tenth caudal vertebra (11 mm), eleventh caudal vertebra (11.5 mm), twelfth caudal vertebra (12.6 mm), proximal thirteenth caudal vertebra, chevrons, distal radius, distal ulna, scapholunare, semilunate carpal, metacarpal I (11 mm), phalanx I-1 (~27 mm), manual ungual I (12.8 mm), metacarpal II (~25 mm), phalanx II-1 (16.1 mm), phalanges II-2 (24.3, 26.6 mm), manual unguals II (~13, 13.2 mm), metacarpal III (~24 mm), phalanx III-1 (6 mm), phalanx III-2 (5.8 mm), phalanges III-3 (15.1, 17.3 mm), manual unguals III (8.5, 9.1 mm), incomplete ilia, pubes (one distal; ~65 mm), ischia (~34 mm), femora (87.5 mm), tibiotarsi (122.4 mm), fibulae, metatarsal I, phalanges I-1 (6.4, 6.5 mm), pedal unguals I (5, 4.9 mm), metatarsals II (one incomplete; 71.8 mm), phalanges II-1 (12.5, ~12 mm), phalanges II-2 (6.4 mm), pedal unguals II (~14 mm), metatarsals III (one incomplete; 78.5 mm), phalanges III-1 (13, 12.5 mm), phalanx III-2 (9.8 mm), phalanx III-3 (8.9 mm), pedal ungual III, metatarsals IV (one incomplete; 76.2 mm), phalanges IV-1 (8.3, 8.8 mm), phalanges IV-2 (7.2, 7.6 mm), phalanx IV-3 (6.2 mm), phalanx IV-4 (~7 mm), pedal ungual IV (8.5 mm), partial pedal phalanx III/IV-? (Dufeau, 2003)
(IGM 100/3500) (adult) maxilla, fused parietals, posterior braincase, dentaries, proximal caudal vertebra, several fragmentary distal caudal vertebrae, distal chevrons, incomplete femur, tibiotarsus, incomplete metatarsal II, phalanx II-1, phalanx II-2, pedal ungual II, incomplete metatarsal III, phalanx III-1, phalanx III-2, phalanx III-3, pedal ungual III, incomplete metatarsal IV, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV (Pei, 2015)
Comments- This specimens were collected in 1997. In the Fighting Dinosaurs: New Discoveries from Mongolia exhibit at the AMNH in 2000, it was displayed with troodontid postcrania. It is mislabeled on the AMNH website that year as the Shuvuuia holotype, though it differs in many respects from that taxon. A braincase analyzed by Franzosa (2004) as the Zos Canyon troodontid and labeled IGM 100/1005 is the same specimen, as Dufeau (2003) includes a photo of the skull labeled "IGM 100/1005 Undescribed troodontid". Hwang et al. (2004) refer to a second Ukhaa Tolgod basal troodontid skull (in addition to Almas), which based on their description I infer to be this specimen. Erickson et al. (2009) examined the femur of an undescribed troodontid they call IGM 100/1129, which is a misprint for this same specimen (Pei, 2015). As of 2009, the skull was labeled IGM 100/1128 at the AMNH (pers. obs. 6-21-2009), which is reflected by its number in Turner's (2008) thesis. By the publications of Turner et al. 2011 and 2012 the entire specimen was called IGM 100/1126, as it is in its unpublished description by Pei (2015). IGM 100/1126 was included in Turner's TWiG analyses (2008; et al., 2011 and 2012), where it emerged as a jinfengopterygine troodontid along with Almas. Pei used a version of Brusatte's TWiG analysis which recovered IGM 100/1126 and Almas closer to troodontines than Sinornithoides or jinfengopterygines. Hartman et al. (2019) used another version of the TWiG analysis and found an intermediate topology where Almas and IGM 100/1126 plus Liaoningvenator are closer to troodontines and Sinornithoides than sinovenatorines/Jinfengopteryx.
References- AMNH, 2000 online. http://paleo.amnh.org/gobi/gobi.swf [requires discontinued Shockwave Flash]
Dufeau, 2003. The cranial anatomy of the theropod dinosaur Shuvuuia deserti (Coelurosauria: Alvarezsauridae), and its bearing upon coelurosaurian phylogeny. Masters Thesis, The University of Texas at Austin. 275 pp.
Franzosa, 2004. Evolution of the brain in Theropoda (Dinosauria). PhD Thesis, The University of Texas at Austin. 357 pp.
Hwang, Norell, Ji and Gao, 2004. A new troodontid from the lower Yixian Formation of China and its affinities to Mongolian troodontids. Journal of Vertebrate Paleontology. 24(3), 73A-74A.
Turner, 2008. Phylogenetic relationships of paravian Theropods. PhD Thesis, Columbia University. 666 pp.
Erickson, Rauhut, Zhou, Turner, Inouye, Hu and Norell, 2009. Was dinosaurian physiology inherited by birds? Reconciling slow growth in Archaeopteryx. PLoS ONE. 4(10), e7390.
Turner, Pol and Norell, 2011. Anatomy of Mahakala omnogovae (Theropoda: Dromaeosauridae), Tögrögiin Shiree, Mongolia. American Museum Novitates. 3722, 66 pp.
Turner, Makovicky and Norell, 2012. A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American Museum of Natural History. 371, 206 pp.
Pei, 2015. New paravian fossils from the Mesozoic of east Asia and their bearing on the phylogeny of the Coelurosauria. PhD thesis, Columbia University. 545 pp.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Harenadraco Lee, Lee, Park, Kim, Badamkhatan, Idersaikhan and Tsogtbaatar, 2024
H. prima Lee, Lee, Park, Kim, Badamkhatan, Idersaikhan and Tsogtbaatar, 2024
Etymology- "The name of the genus is a composition of the Latin words harena (sand) and draco (dragon). The species name "prima" means first in Latin, referring to the taxon being the first troodontid from the Baruungoyot Formation."
Late Campanian, Late Cretaceous
Hermiin Tsav, Baruungoyot Formation, Ömnögovi, Mongolia
Holotype- (IGM 110/119) two right ilial fragments, proximal left femur, distal right femur, incomplete left tibia, incomplete left astragalocalcaneum (~13.1 mm trans), proximal left phalanx I-1, partial left metatarsal II (~105.17 mm), distal left phalanx II-1, left phalanx II-2 (9.46 mm), proximal left pedal ungual II, partial left metatarsal III (118.81 mm), left phalanx III-2 (16.52 mm), left phalanx III-3 (13.36 mm), incomplete pedal ungual III, incomplete left metatarsal IV fused with distal tarsal IV (118.14 mm), proximal left phalanx IV-1, distal left phalanx IV-2, left phalanx IV-3 (10.46 mm), left phalanx IV-4 (9.55 mm), fragments
Diagnosis- (autapomorphies only) tall S-shaped medial margin of medial astragalocalcanear condyle in anterior view; poorly developed flexor sulcus on distal articular end of metatarsal II; metatarsal II lacks collateral ligament fossae; extremely narrow proximal shaft of metatarsal IV; greatly elongated flexor tubercle of pedal ungual II that reaches the shaft of the preceding phalanx when in articulation; distal articular surface of pedal phalanx III-3 not ginglymoid.
Differs from Almas in- anteriorly oriented condyles of astragalocalcaneum (anteroventrally oriented in Almas); no prominent ridge on dorsal surface of distal metatarsal IV shaft.
Differs from Philovenator in- shallow and wide intercondylar groove on astragalocalcaneum; metatarsal II becoming more extensive dorsoventrally at proximal end; dorsal protrusion of proximal ends of metatarsals II and IV; nearly nonexistent exposure of proximal end of metatarsal III in ventral view; modest ventral flange of metatarsal IV with smooth proximal margin (very pronounced ventral flange with an abrupt and stiff proximal margin in Philovenator).
Comments- Discovered in 2018. Unfortunately, Lee et al. (2024) note "the extremely thin nature of the compact bones from the hind limb and their severe microbial erosion prevented proper osteohistological analysis. Determining the exact ontogenetic stage of MPC-D 110/119 is thus currently not feasible..." Although much is made of the proposal Harenadraco is the first troodontid found in the Baruungoyot Formation, Watabe and Suzuki 2000 mention "a Saurornithoides partial skeleton" found on July 18 1997 at Hermiin Tsav, given field number 970719 KmT AMRM-3 which may end up referrable to Harenadraco once described.
Lee et al. (2024) uysed a version of Pei's TWiG analysis to recover Harenadraco as a troodontid that can fall anywhere outside Troodontinae (note their Figure 6 where it is a basal sinovenatorine is based on extended implied weighting). Adding it to my maniraptoromorph analysis from Hartman et al. 2019 results in it being the sister of Almas + Philovenator
Reference- Lee, Lee, Park, Kim, Badamkhatan, Idersaikhan and Tsogtbaatar, 2024. The first troodontid (Dinosauria: Theropoda) from the Upper Cretaceous Baruungoyot Formation of Mongolia. Journal of Vertebrate Paleontology. e2364746.

Almas Pei, Norell, Barta, Bever, Pittman and Xu, 2017
A. ukhaa Pei, Norell, Barta, Bever, Pittman and Xu, 2017
Late Campanian, Late Cretaceous
Ukhaa Tolgod, Djadokhta Formation, Mongolia
Holotype- (IGM 100/1323) (subadult) incomplete skull (~82 mm), sclerotic plates, mandibles (one anterior, one partial), gastralia, posterior three sacral vertebrae, first caudal neural arch, second caudal vertebra, third caudal vertebra, fourth caudal vertebra, fifth caudal vertebra, sixth caudal vertebra, seventh caudal vertebra, eighth caudal vertebra, ninth caudal vertebra, tenth caudal vertebra, eleventh caudal neural arch, five chevrons, partial ilium (56.5 mm), pubes (one incomplete; 60.1 mm), ischia (one partial; 38.5 mm), femora (one partial; 68.3 mm), tibiae (tibiotarsi 94.5, 96.1 mm), fragmentary fibulae, astragalocalcaneum, partial metatarsals II, partial metatarsal III, partial metatarsal IV, metatarsal V, six eggshell fragments
Referred- (IGM 100/972) (juvenile) partial premaxillae, maxillae, nasals, lacrimals, incomplete jugals, anterior frontal, palatal elements, incomplete mandible (Norell, Clark, Demberelyin, Barsbold, Chiappe, Davidson, McKenna, Perle and Novacek, 1994)
(IGM 100/974) (juvenile) incomplete skull, posterior mandible (Norell, Clark, Demberelyin, Barsbold, Chiappe, Davidson, McKenna, Perle and Novacek, 1994)
?(IGM 100/1003) (adult) tooth
....(juvenile) skeleton including cervical vertebrae, dorsal ribs, incomplete femora, tibiae, fibula, metatarsi, pedal phalanges, nineteen eggs, nest (Clark et al., 2002)
Diagnosis- (after Pei et al., 2017) posteriorly curved pterygoid flange; absence of lateral groove on anterior part of dentary; third chevron more than three times as long as corresponding caudal vertebra; distinct spike-like process extending from anterior edge of obturator process on ischium.
Comments- The holotype of Almas was found in 1993, first published as similar to possible Liaoningvenator specimen CAGS-IG01-004 in having teeth of the same number and morphology, and a modified diapsid configuration (Hwang et al., 2004). Hwang (2005; 2007) describes the tooth morphology, while Erickson et al. (2009) examined femoral histology. Hwang (2007) also scored it in an early TWiG analysis, finding it to emerge sister to Byronosaurus. Turner (2008; published as Turner et al., 2012) also included it in a TWiG analysis, finding it to emerge with Jinfengopteryx and IGM 100/1126 as a jinfengopterygine troodontid. This was also found in the related unpublished version shown in Turner et al. (2011). Pei and Norell (2011) briefly described the holotype an an abstract, while Pei (2015) later described Almas in his thesis, which was published as Pei et al. (2017). Pei used a version of Brusatte's TWiG analysis to recover it closer to troodontines than Sinornithoides or jinfengopterygines. The 2017 description doesn't include a phylogenetic analysis but does describe characters placing Almas in that derived position.
Baby Byronosaurus and nest? IGM 100/972 and 100/974 are two juvenile skulls found associated with Citipati nest IGM 100/971 in 1993 (Norell et al., 1994). They were identified by Norell et al. as Velociraptor, based on their long premaxillae (on IGM 100/974 at least). However, Norell and Makovicky (1999) stated that Norell et al. (in press) will show they are actually troodontids. This later became Bever and Norell (2008, 2009), who supported their assignment to Byronosaurus, as did Grellet-Tinner (2005) for 100/972 at least. However, Pei and Norell (2011) referred at least IGM 100/972 to the then-unnamed Almas, based on (taller?) snout shape and less maxillary teeth compared to Byronosaurus, but these are juvenile characters expected in any nestling. Adding to the possibilities, IGM 100/1126 from the Djadohkta has serrationless teeth, and embryonic Troodon lack serrations, so young individuals of the contemporaneous Saurornithoides might as well. Sues and Averianov (2007) mistakenly state IGM 100/974 was reidentified as an oviraptorid, and that the serrationless teeth were actually maxillary palatal bumps, but they were confusing it with embryonic Citipati specimen IGM 100/971.
Discovered in 1995, Norton (DML, 2000) first stated "troodontid nest with 13 hatched eggs and one hatchling skeleton" IGM 100/1003 was on display at the AMNH's Fighting Dinosaurs exhibit. Clark et al. (2002) noted an undescribed Ukhaa Tolgod troodontid nest with juveniles and an adult tooth as being the subject of an upcoming paper, cited as Norell et al., in prep.. Only the eggs have so far been described, in Grellet-Tinner's (2005) thesis. Grellet-Tinner (2005) determined eggshell attached to IGM 100/972's skull is the same as that from that eroded nest, and that 100/972 was found in the same location as 100/1003 but a few meters downhill. As neither 100/972 or 100/974 were in situ in the Citipati nest, it seems plausible they eroded out from 100/1003. If true, and Pei and Norell are correct that 100/972 is not Byronosaurus, this would eliminate referral of any nests or eggs to the latter genus.
The same thing? Pei and Norell (2011) already suggested IGM 100/974 and Almas were the same taxon, and Pei et al. (2017) state that among Djadokhta troodontids, "the Ukhaa perinates IGM 100/972 and IGM 100/974 have a higher chance of being closely related to Almas ukhaa." They correctly note 100/972 lacks a lateral groove on the anterior dentary, and Bever and Norell (2009) also state it has a posteriorly curved lateral flange on its pterygoid (both unpreserved in 100/974), both proposed synapomorphies of Almas. Pei et al.'s objection to them being conspecific is "both specimens were found in a nest of eggs with sizes that are too large to be those of Almas ukhaa", but the perinates were found in a nest of Citipati eggs and the size of the eggs in IGM 100/1003 has not been reported (Grellet-Tinner, 2005).
References- Norell, Clark, Dashzeveg, Barsbold, Chiappe, Davidson, McKenna and Novacek, 1994. A theropod dinosaur embryo, and the affinities of the Flaming Cliffs dinosaur eggs. Science. 266, 779-782.
Norell and Makovicky, 1999. Important features of the dromaeosaurid skeleton II: Information from newly collected specimens of Velociraptor mongoliensis. American Museum Novitates. 3282, 1-45.
Norton, DML 2000. https://web.archive.org/web/20210603191138/http://dml.cmnh.org/2000Jun/msg00082.html
Currie and Dong, 2001. New information on Cretaceous troodontids (Dinosauria, Theropoda) from the People's Republic of China. Canadian Journal of Earth Sciences. 38(12), 1753-1766.
Clark, Norell and Makovicky, 2002. Cladistic approaches to the relationships of birds to other theropod dinosaurs. In Chiappe and Witmer (eds.). Mesozoic Birds: Above the Heads of Dinosaurs. University of California Press. 31-64.
Norell and Hwang, 2004. A troodontid dinosaur from Ukhaa Tolgod (Late Cretaceous Mongolia). American Museum Novitates. 3446, 9 pp.
Hwang, Norell, Ji and Gao, 2004. A new troodontid from the lower Yixian Formation of China and its affinities to Mongolian troodontids. Journal of Vertebrate Paleontology. 24(3), 73A-74A.
Grellet-Tinner, 2005. A phylogenetic analysis of oological characters: A case study of saurischian dinosaur relationships and avian evolution. PhD thesis, University of Southern California. 221 pp.
Hwang, 2005. Phylogenetic patterns of enamel microstructure in dinosaur teeth. Journal of Morphology. 266(2), 208-240.
Averianov and Sues, 2007. A new troodontid (Dinosauria: Theropoda) from the Cenomanian of Uzbekistan, with a review of troodontid records from the territories of the former Soviet Union. Journal of Vertebrate Paleontology. 27(1), 87-98.
Hwang, 2007. Phylogenetic patterns of enamel microstructure in dinosaur teeth. PhD Thesis, Columbia University. 274 pp.
Bever and Norell, 2008. Neonate troodontid skulls from the Upper Cretaceous of Mongolia with observations on the cranial ontogeny of paravian theropods. Journal of Vertebrate Paleontology. 28(3), 52A.
Turner, 2008. Phylogenetic relationships of paravian Theropods. PhD Thesis, Columbia University. 666 pp.
Bever and Norell, 2009. The perinate skull of Byronosaurus (Troodontidae) with observations on the cranial ontogeny of paravian theropods. American Museum Novitates. 3657, 51 pp.
Erickson, Rauhut, Zhou, Turner, Inouye, Hu and Norell, 2009. Was dinosaurian physiology inherited by birds? Reconciling slow growth in Archaeopteryx. PLoS ONE. 4(10), e7390.
Pei and Norell, 2011. A new troodontid (Dinosauria: Theropoda) from the Late Cretaceous Djadokhta Formation of Mongolia. Journal of Vertebrate Paleontology. Program and Abstracts 2011, 172.
Turner, Pol and Norell, 2011. Anatomy of Mahakala omnogovae (Theropoda: Dromaeosauridae), Tögrögiin Shiree, Mongolia. American Museum Novitates. 3722, 66 pp.
Turner, Makovicky and Norell, 2012. A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American Museum of Natural History. 371, 1-206.
Pei, 2015. New paravian fossils from the Mesozoic of east Asia and their bearing on the phylogeny of the Coelurosauria. PhD thesis, Columbia University. 545 pp.
Pei, Norell, Barta, Bever, Pittman and Xu, 2017. Osteology of a new Late Cretaceous troodontid specimen from Ukhaa Tolgod, Ömnögovi Aimag, Mongolia. American Museum Novitates. 3889, 47 pp.

Philovenator Xu, Zhao, Sullivan, Tan, Sander and Ma, 2012
P. curriei Xu, Zhao, Sullivan, Tan, Sander and Ma, 2012
Late Campanian, Late Cretaceous
Wulansuhai Formation, Inner Mongolia, China
Holotype- (IVPP V10597) (~.68 m; 1.1 kg; subadult) femur (86.5 mm), incomplete tibiotarsus (~105 mm), incomplete fibula, metatarsal I (4 mm), proximal phalanx I-1, tarsometatarsus (mtII 94 mm, mt III 107 mm, mtIV 105 mm), phalanx II-1 (10.5 mm), phalanx II-2 (8.4 mm), proximal pedal ungual II, phalanx III-1 (14.5 mm), phalanx III-2 (12 mm), proximal phalanx III-3, phalanx IV-1 (11 mm), phalanx IV-2 (10.5 mm), phalanx IV-3 (9 mm), phalanx IV-4 (9 mm), pedal ungual IV (8 mm), metatarsal V (21.5 mm)
Diagnosis- (after Xu et al., 2012) prominent process on medial side of femoral shaft slightly proximal to the distal end; sheet-like cnemial crest that expands significantly anteriorly; astragalocalcaneal condyles deep anteroposteriorly and separated by deep and narrow groove; extremely long and slender tarsometatarsus (tarsometatarsus/femur length ratio 1.25, tarsometatarsus length/width ratio 22.0); anteroposterior depth much greater than transverse width at mid-shaft of tarsometatarsus; prominent, elongate posterior flange that extends along most of metatarsal IV; metatarsal IV flange about equal in depth to shaft.
Comments- The holotype was found in 1988, reported by Dong et al. (1989) as "a well preserved hindlimb of a juvenile Saurornoithoides", and originally described by Currie and Peng (1994) as a possible juvenile Saurornithoides mongoliensis. Norell et al. (2009) believed this specimen to be merely Troodontidae indet., as they stated hindlimb elements were undiagnostic in Saurornithoides and Zanabazar. More recently, Xu et al. (2012) have reexamined the specimen and found it to be a subadult of a new taxon of troodontid named Philovenator, recovered as a troodontine in a version of Senter's TWiG analysis. A smaller analysis of troodontids and hindlimb characters refined it as sister to Linhevenator in that clade.
References- Dong, Currie and Russell, 1989. The 1988 field program of the Dinosaur Project. Vertebrata Palasiatica. 27(3), 233-236.
Currie and Peng, 1994. A juvenile specimen of Saurornithoides mongoliensis from the Upper Cretaceous of northern China. Canadian Journal of Earth Sciences. 30(10), 2224-2230.
Currie and Dong, 2001. New information on Cretaceous troodontids (Dinosauria, Theropoda) from the People's Republic of China. Canadian Journal of Earth Sciences. 38(12), 1753-1766.
Norell, Makovicky, Bever, Balanoff, Clark, Barsbold and Rowe, 2009. A review of the Mongolian Cretaceous dinosaur Saurornithoides (Troodontidae: Theropoda). American Museum Novitates. 3654, 63 pp.
Xu, Zhao, Sullivan, Tan, Sander and Ma, 2012. The taxonomy of the troodontid IVPP V 10597 reconsidered. Vertebrata PalAsiatica. 50(2), 140-150.

Tamarro Sellés, Vila, Brusatte, Currie and Galobart, 2021
T. insperatus Sellés, Vila, Brusatte, Currie and Galobart, 2021
Late Maastrichtian, Late Cretaceous
Talarn Formation, Tremp Group, Spain
Holotype- (MCD-7073) (subadult) incomplete metatarsal II (~140 mm)
Diagnosis- (After Sellés et al., 2021) metatarsal II with marked plantar ridge; small foramen on lateral surface of plantar ridge of metatarsal II; subarctometatarsalian condition with the metatarsal III restricted to the plantar margin on its proximal part.
Comments- This was discovered in September 2003. Sellés et al. (2021) used Hartman et al.'s maniraptoromorph analysis to recover Tamarro as a jinfengopterygine troodontid in a trichotomy with IGM 100/140 and 100/1128, with Philovenator and Liaoningvenator successively further out.
Reference- Sellés, Vila, Brusatte, Currie and Galobart, 2021. A fast‑growing basal troodontid (Dinosauria: Theropoda) from the latest Cretaceous of Europe. Scientific Reports. 11:4855.

unnamed clade (Daliansaurus liaoningensis + Troodon formosus)
Comments- This clade contains all troodontids with enlarged serrations, so isolated teeth with such are listed here. Note some members have small or absent serrations, however.

Koparion Chure, 1994
K. douglassi Chure, 1994
Early Tithonian, Late Jurassic
Quarry 94, Brushy Basin Member of the Morrison Formation, Utah, US
Holotype- (DINO 3353) maxillary tooth (2 mm)
Diagnosis- differs from Sinusonasus, Sinornithoides and "Saurornithoides" asiamericanus in having mesial serrations on lateral teeth; differs from Sinornithoides, "Saurornithoides" asiamericanus, Saurornithoides and Troodon in having comparatively smaller distal serrations; differs from "Saurornithoides" asiamericanus, Saurornithoides and Troodon in having distal serrations which are not hooked apically.
Comments- Chure's (1995) reference to "teeth ... most similar to ... troodontids" from Dinosaur National Monument in Utah probably refers to Koparion.
Although Chure no longer thinks Koparion is a troodontid (pers. comm. to Harris, 1997; in Naish, DML 1997), there are no other suggested phylogenetic placements which are supported by the evidence. Rauhut (2000) suggested it might be a compsognathid, but Compsognathus differs in lacking mesial serrations. Compsognathus-like teeth from Guimarota described by Zinke (1998) do have mesial serrations, but Koparion differs in having blood pits, and less serrations per mm on both carinae (8 and 7 on mesial and distal vs. 10-17 and 10-15 in cf. Compsognathus) despite similar crown size. These are more similar to derived troodontids. The only other theropods with constricted tooth bases and serrated teeth are Richardoestesia-like taxa and therizinosaurs. Richardoestesia and related taxa differ in having highly elongate teeth with extremely numerous serrations with no blood pits. Therizinosauroids have much larger serrations (~3/mm in Beipiaosaurus and Alxasaurus), while Falcarius' serration size is comparable. However, maxillary teeth of Falcarius have convex distal edges with serrations smaller in comparison to tooth size. Smaller posterior dentary teeth are schematically illustrated as being more recurved, so may be more comparable to Koparion. Therizinosaurs also lack blood pits. Koparion differs from Sinusonasus in having mesial serrations, though they are similar in having small distal serrations without apically hooked tips. It differs from Sinornithoides and "Saurornithoides" asiamericanus in having comparatively smaller distal serrations (Currie and Dong, 2001), and having mesial serrations on non-premaxillary teeth. It further differs from "Saurornithoides" americanus in having distal serrations whose tips are not hooked.
References- Chure and Britt, 1993. New data on theropod dinosaurs from the Late Jurassic Morrison Fm. (MF). Journal of Vertebrate Paleontology. 13(3), 30A.
Chure, 1994. Koparion douglassi, a new dinosaur from the Morrison Formation (Upper Jurassic) of Dinosaur National Monument; The oldest troodontid (Theropoda: Maniraptora). Brigham Young University Geological Studies. 40, 11-15.
Chure, 1995. The teeth of small theropods from the Morrison Formation (Upper Jurassic: Kimmeridgian), UT. Journal of Vertebrate Paleontology. 15(3), 23A.
Naish, DML 1997. https://web.archive.org/web/20190623204709/http://dml.cmnh.org/1997Jan/msg00325.html
Zinke, 1998. Small theropod teeth from the Upper Jurassic coal mine of Guimarota (Portugal). Palaontologische Zeitschrift. 72(1/2) 179-189.
Rauhut, 2000. The interrelationships and evolution of basal theropods (Dinosauria, Saurischia). Ph.D. dissertation, University of Bristol, Bristol. 583 pp.
Currie and Dong, 2001. New information on Cretaceous troodontids (Dinosauria, Theropoda) from the People’s Republic of China. Canadian Journal of Earth Sciences. 38, 1753-1766.

"Saurornithoides" asiamericanus (Nessov, 1995) Olshevsky, 2000
= Pectinodon "asiamericanus" Nessov, 1985
= Saurornithoides "asiamericanus" (Nessov, 1985) Olshevsky, 1991
= Troodon asiamericanus Nessov, 1995
Early Cenomanian, Late Cretaceous
Khodzhakul Formation, Uzbekistan
Holotype- (CCMGE 49/12176) posterior dentary tooth (~3.5x~2.4x~1.1 mm)
Referred- (ZIN PH 1883/16) tooth (Averianov and Sues, 2016)
(ZIN PH 1884/16) tooth (Averianov and Sues, 2016)
(ZIN PH 1885/16) anterior dentary tooth (Averianov and Sues, 2007)
(ZIN PH 1886/16) anterior dentary tooth (Averianov and Sues, 2007)
(ZIN PH 1888/16) maxillary tooth (Averianov and Sues, 2007)
(ZIN PH 1889/16) tooth (Averianov and Sues, 2016)
(ZIN PH 1890/16) tooth (Averianov and Sues, 2016)
(ZIN PH 1891/16) tooth (Averianov and Sues, 2016)
?(ZIN PH 2355/16) distal caudal vertebra (Averianov and Sues, 2016)
?(ZIN PH 2356/16) distal caudal vertebra (Averianov and Sues, 2016)
?(ZIN PH 2357/16) distal caudal vertebra (Averianov and Sues, 2016)
?(ZIN PH 2358/16) distal caudal vertebra (Averianov and Sues, 2016)
Comments- The holotype tooth was originally distinguished from Troodon formosus by its smaller size, more labiolingually compressed crowns, unserrated mesial carina and smaller distal serrations (Nessov, 1995). However, these characters are also seen in more basal troodontids such as Sinornithoides and Sinusonasus (Averianov and Sues, 2004). The referred teeth are indistinguishable from the holotype.
References- Nessov, 1985. New mammals from the Cretaceous of the Kyzylkum. Vestnik Leningradskogo Universiteta. Seriya 7, 8-18.
Olshevsky, 1991. A revision of the parainfraclass Archosauria Cope, 1869, excluding the advanced Crocodylia. Mesozoic Meanderings. 2, 196 pp.
Nessov, 1995. Dinosaurs of northern Eurasia: New data about assemblages, ecology, and paleobiogeography. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University. 156 pp.
Olshevsky, 2000. An annotated checklist of dinosaur species by continent. Mesozoic Meanderings. 3, 157 pp.
Averianov and Sues, 2007. A new troodontid (Dinosauria: Theropoda) from the Cenomanian of Uzbekistan, with a review of troodontid records from the territories of the former Soviet Union. Journal of Vertebrate Paleontology. 27(1), 87-98.
Averianov and Sues, 2016. Troodontidae (Dinosauria: Theropoda) from the Upper Cretaceous of Uzbekistan. Cretaceous Research. 59, 98-110.

Urbacodon? norelli Wang, Ding, Tan, Yang, Zhang and Tan, 2024
Etymology- "The new species was named in honour of the American vertebrate palaeontologist Dr Mark A. Norell, acknowledging his significant leadership and contributions to expeditions and fossil discoveries in the Gobi Desert since the early 1990s."
Middle-Late Campanian, Late Cretaceous
Iren Dabasu Formation, Inner Mongolia, China
Holotype- (LH PV38) anterior right dentary (~58 mm long through d19) (d19 8.42x3.47x2.98 mm), tooth (4.3x2.49x2.33 mm)
Diagnosis- (after Wang et al., 2024; unique combination of) two dentary symphyseal foramina (also in Troodon); anterior and ventral margins of dentary meeting below second dentary alveolus; absence of dentary chin.
Other diagnoses- Wang et al. also list "the presence of a common groove hosting the anterior 12 closely-packed dentary teeth", compared to 15 teeth in U. itemirensis, but the number in Xixiasaurus is unknown due to incompleteness. Similarly "the presence of relatively larger dentary teeth" [than U. itemirensis] is exceeded by Xixiasaurus (see below).
Comments- Found in the late 1990s. Wang et al. state it was found at the "China-Soviet Union joint expedition locality", which means it was collected at Currie and Eberth's 1993 localities K (= AMNH locality 141?), L or P
While Wang et al. described this as a new species of the Cenomanian Urbacodon, but they did not include the Coniacian-Campanian Xixiasaurus in their analysis. They diagnosed Urbacodon based on the following characters- strap-like and lightly-built dentary with medially curved anterior end; symphyseal foramina; rugose symphyseal facet; incrassate-shaped dentary teeth (width greater than 60% of length). While not figured in dorsal/ventral view, Lu et al. describe the dentary of Xixiasaurus as "slightly inflected medially", state it possesses "a distinct foramen is confluent with the inferior alveolar canal ... identical to the condition in Urbacodon itemirensis", and all troodontid dentaries could be described as "strap-like and lightly-built." Regarding the symphyseal facet, norelli has an anteroposteriorly wide facet which is "slightly rugose", Urbacodon has a slightly narrower facet that is "only slightly rugose" and Xixiasaurus has a very narrow facet that appears smooth. Finally, none of the three erupting tooth crowns of Urbacodon nor the three dentary tooth crowns of Xixiasaurus have been measured to indicate their thickness. Taking the specific diagnosis into account, Urbacodon and perhaps Xixiasaurus have a single symphyseal foramen unlike norelli; the anteroventral dentary corner is below the second tooth in norelli, the fifth or sixth in Urbacodon and the fourth or fifth in Xixiasaurus; and Xixiasaurus and Urbacodon are more similar to each other than norelli in having a chin. Wang et al. say "A total of 20 alveoli were identified in the 65-mm-long preserved dentary (Figs 1b and 2b). In U. itemirensis, the 72-mm-long dentary tooth row accommodates 32 teeth, with the anterior 20 alveoli spanning only 35 mm (Averianov and Sues, 2007). This suggests that not only are the teeth themselves proportionally smaller in U. itemirensis compared to those in U. norelli, but they are also more densely packed in the former taxon." What this doesn't establish is the necessary similar size of the individuals, so that alveolar density per a given length is meaningful. As Xixiasaurus has the least preserved alveoli (12 definable in medial view), dentary depth at the posterior edge of the twelfth alveolus is used here to estimate size. Using this metric, the first twelve alveoli of Xixiasaurus are over 2.23 times the height at alveolus 12, those of Urbacodon are at 1.85 times the height of alveolus 12, and those of norelli are 2.05 times the height of alveolus 12. Thus Wang et al. were correct that the teeth of norelli are relatively larger than Urbacodon, and furthermore Xixiasaurus' are even larger. In total, norelli is less similar to Urbacodon and Xixiasaurus than they are to each other in- wider symphyseal facet; two symphyseal foramina; anteriorly located anteroventral dentary corner (under second alveolus vs ~fifth); no dentary chin. Xixiasaurus is the outlier in having a narrower symphyseal facet; smooth symphyseal facet; largest teeth; so Wang et al.'s placement of norelli in Urbacodon instead of Xixiasaurus does not survive scrutiny. Thus the species is placed here at the common ancestor of both and should probably deserve its own genus.
Wang et al. (2024) recovered this sister to Urbacodon itemirensis, with both sister to Zanabazar, using a version of Brusatte's TWiG analysis. Added to a version of Mortimer's maniraptoromorph analysis, it emerged sister to Xixiasaurus, hence the in depth comparison above.
Reference- Wang, Ding, Tan, Yang, Zhang and Tan, 2024 online. A new Urbacodon (Theropoda, Troodontidae) from the Upper Cretaceous Iren Dabasu Formation, China: Implications for troodontid phylogeny and tooth biology. Cladistics. Early View. DOI: 10.1111/cla.12592

unnamed troodontid (Currie, Rigby and Sloan, 1990)
Late Campanian, Late Cretaceous
Dinosaur Park Formation of the Judith River Group, Alberta, Canada
Material- (RTMP 79.8.635) tooth (3.3 mm) (Currie, Rigby and Sloan, 1990)
(RTMP 85.30.1) tooth (Currie, Rigby and Sloan, 1990)
(RTMP 2000.19.1) tooth (5.5 mm) (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 2000.20.1) tooth (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 2000.21.11) tooth (5.2 mm) (Sankey, Brinkman, Guenther and Currie, 2002)
Late Maastrichtian, Late Cretaceous
Lance Formation, Montana, Wyoming, US
(AMNH 8114) tooth (Estes, 1964)
?(AMNH 27117) eleven teeth (Estes, 1964; AMNH online)
Diagnosis- (after Sankey et al., 2002) tooth crowns flattened or concave on one side; enamel pitted on flat/concave side; two well-developed longitudinal ridges present on flat surface, one ridge extending from the apex denticle to near the base of the enamel and the second extending along the anterior carina; mesial serrations always absent; distal serrations rounded.
Comments- This tooth morphology was considered a pathological varient of Troodon formosus by Currie et al. (1990), who referred to it as "Paronychodon" (Troodon). Sankey et al. (2002) considered it a valid taxon though, based on its differing temporal and spatial distribution than Troodon formosus. Specifically, this taxon is restricted to the upper Dinosaur Park Formation within the Judith River Group, and has not been reported from the Prince Creek Formation where T. formosus is common. Sankey et al. also referred teeth described by Estes (1964) as cf. Saurornithoides sp. from the Lance Formation to this species, based on figured specimen AMNH 8114. Troodon bakkeri from that formation is not the same as this taxon, as it has pointed distal serrations like Troodon formosus. It's highly possible additional Late Cretaceous North American teeth currently identified as Troodon belong to this taxon.
References- Estes, 1964. Fossil vertebrates from the Late Cretaceous Lance Formation, eastern Wyoming. University of California Publications in Geological Sciences. 49, 1-180.
Currie, Rigby and Sloan, 1990. Theropod teeth from the Judith River Formation of southern Alberta, Canada. In Carpenter and Currie (eds.). Dinosaur Systematics: Perspectives and Approaches. Cambridge University Press. 107-125.
Sankey, Brinkman, Guenther and Currie, 2002. Small theropod and bird teeth from the Late Cretaceous (Late Campanian) Judith River Group, Alberta. Journal of Paleontology. 76(4), 751-763.

undescribed Troodontidae (Kirkland, Lucas and Estep, 1998)
Late Maastrichtian, Late Cretaceous
North Horn Formation, Utah, US
Material- (BYU coll.) nest, 13 eggs (~170x~76 mm) (Difley, Britt and Policelli, 2004)
(BYU coll.) nest, eggs (Difley, Britt and Policelli, 2004)
(OMNH coll.) teeth (Cifelli, Nydam, Eaton, Gardner, Kirkland, 1999)
Comments- Kirkland et al. (1998) and Cifelli et al. (1999) list Troodontidae gen. et sp. indet. from the North Horn Formation. Difley et al. (2004) report two nests of Prismatoolithus eggs referrable to Troodontidae.
References- Kirkland, Lucas and Estep, 1998. Cretaceous dinosaurs of the Colorado plateau. In Lucas, Kirkland and Estep (eds.). Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science Bulletin. 14, 79-89.
Cifelli, Nydam, Eaton, Gardner, Kirkland, 1999. Vertebrate faunas of the North Horn Formation (Upper Cretaceous-Lower Paleocene), Emery and Sanpete counties, Utah. In Gillette (ed.). Vertebrate Paleontology in Utah. Utah Geological Survey, Miscellaneous Publication. 99-1, 378-388.
Difley, Britt and Policelli, 2004. A troodontid nest in the North Horn Formation, central Utah. Journal of Vertebrate Paleontology. 24(3), 115A.

unnamed Troodontidae (Estes and Sanchiz, 1982)
Late Hauterivian-Early Barremian, Early Cretaceous
Castellar Formation, Spain
Material- (MPT coll.) teeth (~1.2x~.9x? mm)
Comments- These were referred to Coeluridae by Estes and Sanchiz (1982) based on resemblence to cf. Saurornithoides tooth AMNH 8114 of Estes (1964), now identified as a troodontine. Estes and Sanchiz noted the Spanish specimens have smaller serrations though, which closely matches dentary teeth of e.g. Daliansaurus and Sinornithoides. As in that taxon, mesial serrations are absent.
References- Estes, 1964. Fossil vertebrates from the Late Cretaceous Lance Formation, eastern Wyoming. University of California Publications in Geological Sciences. 49, 1-180.
Estes and Sanchiz, 1982. Early Cretaceous lower vertebrates from Galve (Teruel), Spain. Journal of Vertebrate Palaeontology. 2(1), 21-39.

unnamed Troodontidae (Novikov, Lebedev and Alifanov, 1998)
Aptian-Albian, Early Cretaceous
Ilek (=Shestakovo) Formation, Russia
Material- (PM TGU 16/5-124) maxillary or posterior dentary tooth (~2.7x2.1x1 mm) (Averianov and Sues, 2007)
(PM TGU coll.) caudal vertebra (Averianov and Sues, 2007)
(PM TGU coll.) metacarpal I (Averianov and Sues, 2007)
(private coll.) ?dentary with teeth (~10 mm), ?tibiotarsus (Alifanov et al., 1999)
Comments- Alifanov et al. (1999a, b) state "materials included lower leg and jawbone with small teeth with a height of about 1 cm. The latter are characterized by a strong arcuate curvature of the leading edge and the development of a rounded pre-root protrusion at the posterior edge" (translated). Averianov and Sues (2007) report it "was excavated at the Shestakovo 3 site by a commercial collector from Novosibirsk and was unfortunately unavailable for study." They describe an isolated tooth PM TGU 16/5-124 with 13 hooked serrations (5.1/mm) only present distally, but say "the first metacarpal and caudal from Shestakovo 1 will be described elsewhere."
References- Novikov, Lebedev and Alifanov, 1998. New Mesozoic vertebrate fossil sites of Russia. Third European Workshop on Vertebrate Paleontology, p. 58.
Alifanov, Efimov, Novikov and Morales, 1999a. Novyy psittakozovrovyy kompleks tetrapod iz nizhnemelovogo mestonakhozhdeniya Shestakovo (yuzhnaya Sibir'). Doklady Akademii Nauk. 369(4), 491-493.
Alifanov, Efimov, Novikov and Morales, 1999b. A new psittacosaurian complex of tetrapods from the Lower Cretaceous Shestakovo locality (southern Siberia). Doklady Earth Sciences. 369A(9), 1228-1230.
Leshchinskiy, Voronkevich, Fayngertz, Maschenko, Lopatin and Averianov, 2001. Early Cretaceous vertebrate locality Shestakovo, western Siberia, Russia: A refugium for Jurassic relicts? Journal of Vertebrate Paleontology. 21(3), 73A.
Averianov and Sues, 2007. A new troodontid (Dinosauria: Theropoda) from the Cenomanian of Uzbekistan, with a review of troodontid records from the territories of the former Soviet Union. Journal of Vertebrate Paleontology. 27(1), 87-98.

unnamed troodontid (Zhao, 2003)
Cenomanian, Late Cretaceous
Liantoutang Formation, Zhejiang, China
Material- (ZMNH M8711) two nests of five and fourteen eggs
Comments- These are referred to the ootaxon Prismatoolithus sp., suggesting they are more closely related to Troodon than Philovenator.
References- Zhao, 2003. The nesting behavior of troodontid dinosaurs. Vertebrata PalAsiatica. 41, 157-168.
Varricchio, Jin and Jackson, 2015. Lay, brood, repeat: Nest reuse and site fidelity in ecologic time for two Cretaceous troodontid dinosaurs. Journal of Vertebrate Paleontology. 35(3), e932797. DOI: 10.1080/02724634.2014.932797

unnamed troodontid (Barsbold, Osmólska and Kurzanov, 1987)
Aptian-Albian, Early Cretaceous
Dzunbain Formation, Mongolia
Material- (IGM 100/44) quadrate, baincase fragment, dentary fragment, posterior mandible, four teeth (2.5-3 mm), five partial cervical neural arches (22-25 mm), semilunate carpal, metacarpal I (15 mm), phalanx I-1 (36 mm), manual ungual I (18 mm), metacarpal II (40 mm), phalanx II-1 (26 mm), incomplete phalanx II-2 (24 mm), manual ungual II, metacarpal III (~37 mm), manual ungual III, distal femur, metatarsal I (13 mm), phalanx I-1 (13 mm), distal metatarsal II, phalanx II-1 (25 mm), phalanx II-2 (17 mm), pedal ungual II (~20 mm), distal metatarsal III (~108 mm), phalanx III-1 (29 mm), phalanx III-2 (17 mm), phalanx III-3 (~12 mm), distal metatarsal IV, phalanx IV-1 (19 mm), phalanx IV-2 (~13 mm), pedal ungual IV fragment
Comments- Discovered in 1979, this is notable as being the first described Early Cretaceous specimen recognized as being troodontid, until the description of Sinornithoides in 1994. The specimen has gained notoriety for being included in all TWiG analyses since 2004 as the 'Early Cretaceous troodontid'. While described by Barsbold et al. as Troodontidae indet., its unique character combination in matrices indicates future authors should compare IGM 100/44 in depth to the many Early Cretaceous troodontids now known to determine its validity. Although Barsbold et al. initially placed the specimen in the Barunbayaskaya Svita, its Khamryn-Us locality has most recently been referred to the Dzunbain Formation (e.g. description of the co-occuring Mongolostegus).
Reference- Barsbold, Osmólska and Kurzanov, 1987. On a new troodontid (Dinosauria, Theropoda) from the Early Cretaceous of Mongolia. Acta Palaeontologica Polonica. 32(1-2), 121-132.

Daliansaurus Shen, Lü, Liu, Kundrát, Brusatte and Gao, 2017
D. liaoningensis Shen, Lü, Liu, Kundrát, Brusatte and Gao, 2017
Early Aptian, Early Cretaceous
Lujiatun Beds of Yixian Formation, Liaoning, China
Holotype- (DNHM D2885) (~1 m; 4 year old adult) partial skull (~138 mm), incomplete mandibles, nine cervical vertebrae with fused cervical ribs, thirteen dorsal vertebrae, fifteen dorsal ribs (seven partial), two uncinate processes, five sacral vertebrae, first to twenty-eighth caudal vertebrae, seven chevrons, humeri (82.9 mm), radii (65.2, 65.7 mm), ulnae (65, 64.7 mm), semilunate carpals, metacarpals I (15.7, 14.1 mm), phalanges I-1 (28.7, 31.1 mm), manual unguals I (16.6, 25.4 mm), metacarpals II (30.5, 31.5 mm), phalanges II-1 (~20.5, 23.2 mm), phalanges II-2 (27.5, 27.8 mm), manual unguals II (20.8, 19.9 mm), metacarpals III (~31, 32 mm), phalanx III-1 (7.5 mm), phalanx III-2 (8.7 mm), phalanges III-3 (19.2 mm), manual unguals III (19.7, 19.1 mm), ilia (82.3, 92.8 mm), distal ischium, femur (130.8 mm), tibiotarsus (190.1 mm), fibula, metatarsal I, phalanx I-1 (11.3 mm), pedal ungual I (13.3 mm), metatarsal II (98.1 mm), phalanx II-1 (20.1 mm), phalanx II-2 (14.7 mm), incomplete pedal ungual II (22.7 mm), metatarsal III, partial phalanx III-1, metatarsal IV (110.1 mm) , phalanx IV-1 (15.9 mm), phalanx IV-2 (14.8 mm), phalanx IV-3 (13.3 mm), phalanx IV-4 (11.3 mm), pedal ungual IV (20.8 mm)
Diagnosis- (after Shen et al., 2017) uncinate processes on dorsal ribs (among troodontids); pedal ungual IV robust, deep, and approximately the same size as pedal ungual II. Differs from Sinusonasus in that metatarsal II terminates before trochlea of metatarsal IV begins; metatarsal IV lacks prominent longitudinal flange.
Other diagnoses- Shen et al. (2017) state "Daliansaurus differs from Sinovenator and Sinusonasus in that ... in that metacarpal II is slightly shorter than metacarpal III (instead of longer)" but the manus is unknown in Sinusonasus.
Comments- Discovered prior to June 2016, this was described as a sinovenatorine troodontid sister to Sinusonasus by Shen et al. (2017) using Brusatte's version of the TWiG dataset. Hartman et al. (2019) used a more extensive version of the TWiG analysis to recover it and Sinusonsus in a clade closer to troodontines than sinovenatorines. Forcing Daliansaurus into Sinovenatorinae takes 4 more steps.
References- Shen, Lü, Liu, Kundrát, Brusatte and Gao, 2017. A new troodontid dinosaur from the Lower Cretaceous Yixian Formation of Liaoning Province, China. Acta Geologica Sinica. 91(3), 763-780.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247
Shen, Lü, Gao, Hoshino, Uesugi and Kundrát 2019. Forearm bone histology of the small theropod Daliansaurus liaoningensis (Paraves: Troodontidae) from the Yixian Formation, Liaoning, China. Historical Biology. 31(2), 253-261.

Tochisaurus Kurzanov and Osmólska, 1991
T. nemegtensis Kurzanov and Osmólska, 1991
Early Maastrichtian, Late Cretaceous
Nemegt, Nemegt Formation, Mongolia
Holotype- (PIN 551-224) (~2.8 m) metatarsal II (233 mm), metatarsal III (232 mm), metatarsal IV (242 mm)
Diagnosis- (after Kurzanov and Osmólska, 1991) long, slender metatarsus; strongly reduced metatarsal II.
Comments- This was found in 1948 and originally figured by Kurzanov (1987) as an unknown theropod, then identified by Osmólska (1987) as a troodontid. Although Osmólska speculated it might be a specimen of Borogovia, Kurzanov and Osmólska (1991) noted the distal end of metatarsal II is far more reduced in Tochisaurus. Similarly, Tochisaurus differs from Zanabazar in having metatarsal II narrower proximally, and the proximal surface of the metatarsus inclined. It could not be compared to the earlier Saurornithoides, however. Tochisaurus was not included in published phylogenetic analyses until that of Hartman et al. (2019), where it fell out sister to the earlier Daliansaurus. While this should be considered provisional given the incomplete holotype of Tochisaurus, it is notable that Daliansaurus has Kurzanov and Osmólska's two proposed Tochisaurus auatpomorphies but to a more extreme degree.
References- Kurzanov, 1987. Avimimidae and the problem of the origin of birds. Trudy, Sovmestnaa Sovetsko-Mongolskaa paleontologiceskaa ekspedicia. 31, 1-95.
Osmólska, 1987. Borogovia gracilicrus gen. et sp. n., a new troodontid dinosaur from the Late Cretaceous of Mongolia. Acta Palaeontologica Polonica. 32, 133-150.
Kurzanov and Osmólska, 1991. Tochisaurus nemegtensis gen. et sp. n., a new troodontid (Dinosauria, Theropoda) from Mongolia. Acta Palaeontologia Polonica. 36, 69-76.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Hesperornithoides Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019
H. miessleri Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019
Late Kimmeridgian, Late Jurassic
Jimbo Quarry, Brushy Basin Member of the Morrison Formation, Wyoming, US
Holotype- (WYDICE-DML-001; = WDC DML0001; Lori) (~.89 m; adult) incomplete skull (~66 mm), incomplete mandibles, hyoids, partial axis, third cervical vertebra (11.7 mm), fourth cervical vertebra (~14 mm), ?sixth cervical vertebra (14.5 mm), eighth cervical vertebra (13.7 mm), cervical ribs, first dorsal vertebra (11.7 mm), anterior dorsal rib, four mid caudal vertebrae (two partial; 20.8, 22.3 mm), seven distal caudal vertebrae (three fragmentary; 22.3, 23.6, 18.2, 17.5 mm), five chevrons, partial scapula, partial coracoid, partial furcula, proximal humerus, distal humerus, radius, ulna (46.4 mm), scapholunare, semilunate carpal, metacarpal I (16.9 mm), manual ungual I (17.1 mm), metacarpal II, manual ungual II (15.5 mm), metacarpal III, phalanx III-2 (7 mm), phalanx III-3 (18.2 mm), manual ungual III (14.4 mm), ilial fragment, incomplete femur, tibiae (168 mm), fibulae, astragalus, calcaneum, distal tarsal, metatarsal I, incomplete metatarsals II, pedal ungual II, incomplete metatarsals III, phalanx III-1 (26.3 mm), phalanx III-2 (17.3 mm), phalanx III-3, pedal ungual III (13.6 mm), incomplete metatarsals IV, phalanx IV-1, phalanx IV-2 (13.2 mm), phalanx IV-3 (~8.5 mm), phalanx IV-4 (6.9 mm), proximal pedal ungual IV, pedal claw sheath, metatarsal V
Diagnosis- (after Hartman et al., 2019) pneumatic jugal (also in Zanabazar and some eudromaeosaurs among maniraptorans); short posterior lacrimal process (<15% of ventral process length, measured from internal corner; also present in Zanabazar, Archaeopteryx, and Epidexipteryx); quadrate forms part of lateral margin of paraquadrate foramen; small external mandibular fenestra (<12% of mandibular length; also in Zhenyuanlong and Dromaeosaurus among non-avian paravians); humeral entepicondyle >15% of distal humeral width (also in some avialans); manual ungual III subequal in size to ungual II (also in Daliansaurus, IGM 100/44 and Mahakala); mediodistal corner of tibia exposed anteriorly (also in Archaeopteryx and Jeholornis).
Comments- This specimen was discovered in Summer 2001 and announced in an abstract (Lovelace, 2004). In Hartman et al.'s (2005) preliminary analysis also reported via abstract and Wahl's (2006) thesis, it emerged sister to Sinornithoides using the Mei TWiG matrix. Hartman et al. (2019) officially described and named the taxon, using a new extensive TWiG analysis to place it most parsimoniously sister to Xixiasaurus plus Sinusonasus slightly more stemward in Troodontidae. As they state "a placement as the first branching dromaeosaurid is just two steps longer, supported by the dorsally placed maxillary fenestra, mesial dental serrations, and large lateral teeth. This may be more compatible stratigraphically, but moving Hesperornithoides' clade to a more stemward position in Troodontidae outside Sinovenatorinae, the Liaoningvenator-like taxa and derived troodontids is also only two steps longer. Similarly, in trees two steps longer than the MPTs where troodontids are avialans, Hesperornithoides can be the first branching taxon closer to Aves than troodontids based on homoplasic characters such as the short posterodorsal lacrimal process. Two additional steps also place the taxon in contemporaneous Archaeopterygidae, sister to Caihong which shares [mesial dental serrations, large lateral teeth and elongate but not hypertrophied distal caudal prezygapophyses]. Despite the uncertainty of its position within Paraves, however, Hesperornithoides is strongly supported as a member of the Deinonychosauria plus Avialae clade, as even constraining it to the paravian stem requires 15 additional steps."
References- Lovelace, 2004. Taphonomy and paleoenvironment of a Late Jurassic dinosaur locality in the Morrison Formation of east-central Wyoming. Journal of Vertebrate Paleontology. 24(3), 152A.
Hartman, Lovelace and Wahl, 2005. Phylogenetic assessment of a maniraptoran from the Morrison Formation. Journal of Vertebrate Paleontology. 25(3), 67A-68A.
Wahl, 2006. Osteology and phylogenetic relationships of a new small maniraptoran from the Upper Jurassic of Wyoming. Masters Thesis, Fort Hays State University. 98 pp.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Xixiasaurus Lu, Xu, Liu, Zhang, Jia and Ji, 2010
X. henanensis Lu, Xu, Liu, Zhang, Jia and Ji, 2010
Coniacian-Campanian, Late Cretaceous
Lower-Middle Majiacun Formation, Henan, China
Holotype- (41HIII-0201) anterior skull, anterior dentary, radial fragment, ulnar fragment, phalanx I-1 (36 mm), manual ungual I, distal metacapal II, phalanx II-1 (30 mm), proximal phalanx II-2, distal metacarpal III, distal manual ungual
Diagnosis- (after Lu et al., 2010) distinct opening on the lateral surface of the base of the nasal process of the premaxilla; snout shows a more tapered U-shape than in Byronosaurus; 22 maxillary teeth; mandibular symphyseal region is slightly inflected medially.
Comments- Discovered prior to March 2009, Lu et al. (2010) proposed Xixiasaurus was most closely related to Byronosaurus and Urbacodon based on the lack of dental serrations. However, Hartman et al. (2019) found the distribution of serrations to be highly homoplasic within troodontids, with serrationless teeth primitive for maniraptoriforms but Xixiasaurus itself nested within a clade of serrated taxa (Sinusonasus, Hesperornithoides, Daliansaurus, IGM 100/44).
References- Lu, Xu, Liu, Zhang, Jia and Ji, 2010. A new troodontid (Theropoda: Troodontidae) from the Late Cretaceous of central China, and the radiation of Asian troodontids. Acta Palaeontologica Polonica. 55(3), 381-388.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Sinusonasus Xu and Wang, 2004
S. magnodens Xu and Wang, 2004
Early Aptian, Early Cretaceous
Lujiatun Beds of Yixian Formation, Liaoning, China
Holotype- (IVPP V 11527) (adult) incomplete skull (~109 mm), incomplete mandible, several dorsal ribs, gastralia, sacrum, twenty-seven caudal vertebrae (537 mm), chevrons, pubis (113 mm), ischia (61 mm), femur (141 mm), tibiae (186 mm), fibula (167 mm), metatarsal I (22.7, 19.9 mm), phalanx I-1 (10.2, 12.1 mm), pedal ungual I (15.7, 15.7 mm), metatarsal II (93.5 mm), phalanx II-1 (24.2, 21.2 mm) phalanx II-2 (17.6, 20.6 mm), pedal ungual II (31.1 mm), metatarsal III (~108 mm), phalanx III-1 (28.5 mm), phalanx III-2 (19.1 mm), phalanx III-3 (19.4 mm), pedal ungual III (13.6 mm), metatarsal IV (106.6 mm), phalanx IV-1, phalanx IV-2 (13.7 mm), phalanx IV-3 (14.7 mm), metatarsal V
Diagnosis- (after Xu and Wang, 2004) interantorbital canal absent; nasal sinusoid in lateral view; middle maxillary teeth relatively large; distal chevrons elongated to contact each other anteroposteriorly; femoral neck long.
Comments- The holotype was discovered prior to December 2003. This genus was consistantly mispelled Sinucerasaurus by Xu and Norell (2006), though the latter was written over a year after the publication of Sinusonasus. Xu and Norell (2004) proposed it was closer to troodontines than Sinovenator and Sinornithoides, but Hartman et al. (2019) recovered it intermediate between those two genera.
References- Xu and Wang, 2004. A new troodontid (Theropoda: Troodontidae) from the Lower Cretaceous Yixian Formation of western Liaoning, China. Acta Geologica Sinica. 78(1), 22-26.
Xu and Norell, 2006. Non-avian dinosaur fossils from the Lower Cretaceous Jehol Group of western Liaoning, China. Geological Journal. 41(3-4), 419-437.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

Sinornithoides Russell and Dong, 1994
S. youngi Russell and Dong, 1994
Early Cretaceous
Ejinhoro Formation, Inner Mongolia, China
Holotype- (IVPP V9612) (1.1 m, juvenile) skull (109 mm), hyoid, atlantal neural arch, fourth cervical centrum (18 mm), fifth cervical vertebra (18 mm), sixth cervical prezygapophysis, ninth cervical vertebra (19.1 mm), ninth cervical rib, tenth cervical vertebra (14.4 mm), tenth cervical rib, first dorsal vertebra (13 mm), first dorsal rib, ten pairs of dorsal ribs, fifteen rows of gastralia, (sacrum- 72 mm) sixth sacral vertebra (12 mm), first caudal vertebra (~11.5 mm), first chevron (16.7 mm), second caudal vertebra (~13.5 mm), second chevron (23.8 mm), third caudal vertebra (14.5 mm), fourth caudal vertebra, fifth caudal vertebra, sixth caudal vertebra, seventh caudal vertebra (11.6 mm), seventh chevron (9.2 mm), eighth caudal vertebra (14 mm), ninth caudal vertebra (17.5 mm), tenth caudal vertebra (21.2 mm), eleventh caudal vertebra (21.5 mm), twelfth caudal vertebra (23 mm), thirteenth caudal vertebra (24.5 mm), fourteenth caudal vertebra (23.9 mm), fifteenth caudal vertebra (23 mm), sixteenth caudal vertebra (22.5 mm), seventeenth caudal vertebra (23.5 mm), eighteenth caudal vertebra (22.9 mm), nineteenth caudal vertebra (24 mm), twentieth caudal vertebra (23.8 mm), twenty-first caudal vertebra (23 mm), twenty-second caudal vertebra (22 mm), twenty-third caudal vertebra (18 mm), twenty-fourth caudal vertebra (22.4 mm), twenty-fifth caudal vertebra (~20 mm), twenty-sixth caudal vertebra (~18 mm), twenty-seventh caudal vertebra (~16.8 mm), chevrons, proximal scapula, coracoids (~30 mm long, 27 mm deep), incomplete furcula, humeri (82.8 mm), radius (59.1 mm), ulna (65 mm), scapholunare, semilunate carpal, metacarpal I (11.3, 12.1 mm), phalanx I-1 (29.3 mm), manual ungual I (19.7 mm), metacarpal II (37.1 mm), phalanx II-1 (19 mm), phalanx II-2 (28.5, 28.1 mm), manual ungual II (22, 22 mm), metacarpal III (35 mm), phalanx III-1 (4.2 mm), phalanx III-2 (8.2 mm), phalanx III-3 (20.3 mm), manual ungual III (15.5 mm), ventral ilia (73 mm), pubes (89 mm), ischia (47.5 mm), femora (140 mm), tibiae (197.6 mm), fibulae, astragali (19.2 mm wide), distal tarsal III, distal tarsal IV, metatarsal I (~12.3, 12.3 mm), phalanx I-1 (11.4, 10 mm), pedal ungual I (10.7, 9.5 mm), metatarsal II (100.4, 100.6 mm), phalanx II-1 (20.2, 21.7 mm), phalanx II-2 (11.7 mm), pedal ungual II (19 mm), metatarsal III (111 mm), phalanx III-1 (27.6, 23 mm), phalanx III-2 (20, 19.2 mm), phalanx III-3 (16, 15.8 mm), pedal ungual III (14.6 mm), metatarsal IV (110 mm), phalanx IV-1 (17.8, 18.2 mm), phalanx IV-2 (15.7, 13.9 mm), phalanx IV-3 (13, 11.7 mm), phalanx IV-4 (12.5, 13 mm), pedal ungual IV (11.5 mm), metatarsal V (41.8 mm)
Comments- Note that while volume 30(10) of the Canadian Journal of Earth Sciences lists its date as October 1993, it was not published until February or March of 1994. The holotype was discovered on August 6 1988. Dong (1992) photographs and mentions this specimen as "Saurornithoides new species (Russell and Dong in prep.)" before it was more fully prepared. Russell and Dong (1994) initially proposed the taxon was stemward of Troodon, Zanabazar, Saurornithoides and Borogovia, which has been recovered in all analyses since. Currie and Dong (2001) later described the skeleton in more detail.
Dong (1997) referred a fragmentary specimen (IVPP V11119) to Sinornithoides sp. nov., but it seems to be more basal.
References- Dong, 1992. Dinosaurian Faunas of China. China Ocean Press. 188 pp.
Russell and Dong, 1994. A nearly complete skeleton of a new troodont dinosaur from the Early Cretaceous of the Ordos Basin, Inner Mongolia, People's Republic of China. Canadian Journal of Earth Sciences. 30(10), 2163-2173.
Dong, 1997. On small theropods from Mazongshan area, Gansu province, China. In Dong (ed.). Sino-Japanese Silk Road Dinosaur Expedition. China Ocean Press. 13-18.
Currie and Dong, 2001. New information on Cretaceous troodontids (Dinosauria, Theropoda) from the People's Republic of China. Canadian Journal of Earth Sciences. 38, 1753-1766.
White, 2009. The subarctometatarsus: intermediate metatarsus architecture demonstrating the evolution of the arctometatarsus and advanced agility in theropod dinosaurs. Alcheringa. 33(1), 1-21.

Byronosaurus Norell, Makovicky and Clark, 2000
= "Byranjaffia" Novacek, 2002
B. jaffei Norell, Makovicky and Clark, 2000
Late Campanian, Late Cretaceous
Ukhaa Tolgod, Djadokhta Formation, Mongolia
Holotype- (IGM 100/983) partial skull, incomplete mandibles, posterior axis, incomplete third cervical vertebra, anterior fourth cervical vertebra, fourth cervical rib, two anterior dorsal centra, posterior dorsal vertebrae, dorsal rib fragment, possible sacral centrum, four distal caudal fragments, distal femur (~150 mm), proximal tibia, proximal fibula, limb bone fragments, distal metatarsal II, phalanx II-2, distal phalanx III-2, proximal phalanx III-3
Paratype- (IGM 100/984) premaxillae, anterior maxillae, maxillary fragment, lacrimals, posterior nasals, vomer fragment
Diagnosis- (after Norell et al., 2000) teeth lacking serrations; interfenestral bar not recessed from lateral plane of maxilla; interantorbital canal; shallow groove along the ventrolateral margin the maxilla.
Comments- The holotype was discovered in 1993 and illustrated as an undescribed troodontid in Novacek et al. (1994). Its unassociated remains were mixed with those of ornithomimid specimen IGM 100/987. The paratype was found later on July 15 1996. Novacek (2002) used the name "Byranjaffia" in his book for Byronosaurus. The former is either a misspelling or an unpublished name previously intended for the genus. Both specimens were described briefly by Norell et al. (2000) then later in detail by Makovicky et al. (2003).
Note the nests and juvenile remains referred to Byronosaurus by Bever and Norell (2008- IGM 100/972, 100/974) and Grellet-Tinner (2005- IGM 100/1003) are here placed in Philovenator.
References- Novacek, Norell, McKenna and Clark, 1994. Fossils of the Flaming Cliffs. Scientific American. 271(6), 60-69.
Norell, Makovicky and Clark, 2000. A new troodontid theropod from Ukhaa Tolgod, Mongolia. Journal of Vertebrate Paleontology. 20(1), 7-11.
Novacek, 2002. Time Traveler: In Search of Dinosaurs and Ancient Mammals from Montana to Mongolia. Farrar, Strauss and Giroux. 368 pp.
Makovicky, Norell, Clark and Rowe, 2003a online. Byronosaurus jaffei, Digital Morphology. http://digimorph.org/specimens/Byronosaurus_jaffei/rostrum/
Makovicky, Norell, Clark and Rowe, 2003b online. Byronosaurus jaffei, Digital Morphology. http://digimorph.org/specimens/Byronosaurus_jaffei/braincase/
Makovicky, Norell, Clark and Rowe, 2003. Osteology and relationships of Byronosaurus jaffei (Theropoda: Troodontidae). American Museum Novitates. 3402, 1-32.
Grellet-Tinner, 2005. A phylogenetic analysis of oological characters: A case study of saurischian dinosaur relationships and avian evolution. PhD thesis, University of Southern California. 221 pp.
Bever and Norell, 2008. Neonate troodontid skulls from the Upper Cretaceous of Mongolia with observations on the cranial ontogeny of paravian theropods. Journal of Vertebrate Paleontology. 28(3), 52A.
Erickson, Rauhut, Zhou, Turner, Inouye, Hu and Norell, 2009. Was dinosaurian physiology inherited by birds? Reconciling slow growth in Archaeopteryx. PLoS ONE. 4(10), e7390.

Troodontinae sensu van der Reest and Currie, 2017
Definition- (Gobivenator mongoliensis + Zanabazar junior)
= Troodontinae sensu Kubota, Kobayashi and Ikeda, 2024
Definition- (Troodon formosus + Zanabazar junior + Gobivenator mongoliensis, - Sinovenator changii, Jinfengopteryx elegans) (modified)
References- van der Reest and Currie, 2017. Troodontids (Theropoda) from the Dinosaur Park Formation, Alberta, with a description of a unique new taxon: Implications for deinonychosaur diversity in North America. Canadian Journal of Earth Sciences. 54, 919-935.
Kubota, Kobayashi and Ikeda, 2024. Early Cretaceous troodontine troodontid (Dinosauria: Theropoda) from the Ohyamashimo Formation of Japan reveals the early evolution of Troodontinae. Scientific Reports. 14:16392.

Gobivenator Tsuihiji, Barsbold, Watabe, Tsogtbaatar, Chinzorig, Fugiyama and Suzuki, 2014
G. mongoliensis Tsuihiji, Barsbold, Watabe, Tsogtbaatar, Chinzorig, Fugiyama and Suzuki, 2014
Campanian, Late Cretaceous
Dzamin Khond, Djadochta Formation, Mongolia
Holotype- (IGM 100/86; 070623 DK CHZ) incomplete skull, incomplete mandible, proatlas, atlas, axis (14.6 mm), third to fourth cervical vertebrae, eighth to tenth cervical vertebrae, cervical ribs, twelve dorsal vertebrae (d1 24 mm, d12 21.6 mm), dorsal ribs, gastralia, synsacrum (205.4 mm), thirty-five caudal vertebrae (c1 15.8 mm, c34 19.4 mm), chevrons, scapula (107.9 mm), coracoids, humeri (108.9 mm), proximal radius, proximal ulna, incomplete ilium, pubis (169.4 mm), ischium (~92 mm), femur (~192 mm), proximal tibia, proximal fibula, astragalocalcaneum, metatarsal I, phalanx I-1, pedal ungual I, distal tarsal III, distal tarsal IV, metatarsal II (145.2 mm), phalanx II-1, phalanx II-2, metatarsal III (159.4 mm), metatarsal IV (163 mm), phalanx IV-1, metatarsal V
Campanian, Late Cretaceous
Tugrikin Shire, Djadochta Formation, Mongolia
Referred- ?(HMNS coll.) incomplete skull, incomplete mandibles, partial skeleton including two manual phalanges (Tsogtbaatar and Chinzorig, 2010)
Diagnosis- (after Tsuihiji et al., 2014) pointed anterior end of fused parietal that wedges into V-shaped notch between frontals; gracile anterior, posterior and ventral rami of postorbital; fossa on surangular in front of posterior surangular foramen; dorsoventrally elongated proximal chevrons (up to 4.5 times as long as the height of the preceding caudal vertebrae).
Comments- Gobivenator was discovered on June 15 and/or 23 2007 (Saneyoshi et al., 2010), mentioned as "jaw and associated skeletons of a Troodontidae" with field number 070623 DK CHZ. Whether the partial dentary with teeth shown in figure 8B as "Lower jaw of Troodontidae" belongs to the holotype is unknown, as only the opposite mandible is shown in its description. Tsuihiji et al. (2010) presented the specimen in an abstract, recovering it as sister to Byronosaurus in a preliminary phylogenetic analysis. Tsuihiji et al. (2014) later described the taxon in more detail and named it, this time recovering Gobivenator as sister to troodontines with Byronosaurus very basal based on a version of Senter's TWiG matrix. Most recently, Hartman et al.'s (2019) extensive TWiG matrix found it similarly close to troodontines but with Byronosaurus just slightly more stemward.
A skull photographed by Tsogtbaatar and Chinzorig (2010) as "a troodontid from Tugrikin Shire" (Fig. 3) seems most similar to Gobivenator (~88% of the holotype's size) in that it has the slender postorbital and at least ventrally defined surangular fossa, while strongly differing from Saurornithoides, Byronosaurus, Almas and IGM 100/1126 in various features. Differences such as the narrower interfenestral bar and undeveloped groove on the ventrolateral maxilla, posteriorly angled dorsal jugal process and slender angular could be individual variation or taxonomic. It was originally discovered on August 1 1994 and was misidentified in the field as Velociraptor (field number 940801 TS-I WTB) (Watabe et al., 2000).
References- Watabe and Suzuki, 2000. Report on the Japan - Mongolia Joint Paleontological Expedition to the Gobi desert, 1994. Hayashibara Museum of Natural Sciences Research Bulletin. 1, 30-44.
Saneyoshi, Watabe, Tsubamoto, Tsogtbaatar, Chinzorig and Suzuki, 2010. Report of the HMNSMPC Joint Paleontological Expedition in 2007. Hayashibara Museum of Natural Sciences Research Bulletin. 3, 19-28.
Tsogtbaatar and Chinzorig, 2010. Fossil specimens prepared in Mongolian Paleontological Center: 2002–2008. Hayashibara Museum of Natural Sciences Research Bulletin. 3, 155-166.
Tsuihiji, Watabe, Tsogtbaatar, Suzuki and Barsbold, 2010. A new troodontid (Dinosauria: Theropoda) from the Late Cretaceous of the Gobi Desert, Mongolia. Journal of Vertebrate Paleontology. Program and Abstracts 2010, 177A-178A.
Tsuihiji, Barsbold, Watabe, Tsogtbaatar, Chinzorig, Fugiyama and Suzuki, 2014. An exquisitely preserved troodontid theropod with new information on the palatal structure from the Upper Cretaceous of Mongolia. Naturwissenschaften. 101, 131-142.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247.

Geminiraptor Senter, Kirkland, Bird and Bartlett, 2010
G. suarezarum Senter, Kirkland, Bird and Bartlett, 2010
Barremian, Early Cretaceous
Yellow Cat Member of Cedar Mountain Formation, Utah, US
Holotype- (CEUM 73719) partial maxilla
Diagnosis- (after Senter et al., 2010) maxilla with extensive pneumatization internal to antorbital fossa, inflating the bone so that it has a triangular cross-section; large, anteroposteriorly elongate maxillary fenestra; promaxillary fenestra visible in lateral view; anteroposteriorly narrow promaxillary strut and interfenestral strut; small, square dental alveoli with bony septa between them.
Comments- Discovered in 2004, the holotype is incorrectly listed as CEUM 7319 in the paper (Carpenter, online 2010 Comment to Senter et al., 2010).
Senter et al. (2010) used a version of the TWiG matrix to place Geminiraptor as a troodontid more derived than Sinovenator, but less than troodontines.
References- Carpenter, online 2010. https://journals.plos.org/plosone/article/comment?id=10.1371/annotation/1da07b25-d3db-45e3-a063-c57958012b28
Senter, Kirkland, Bird and Bartlett, 2010. A new troodontid theropod dinosaur from the Lower Cretaceous of Utah. PLoS ONE. 5(12), e14329.
Senter, Kirkland, Deblieux and Madsen, 2010. Three new theropods from the Cedar Mountain Formation (Lower Cretaceous) of Utah. Journal of Vertebrate Paleontology. Program and Abstracts 2010, 162A.

Urbacodon Averianov and Sues, 2007
U. itemirensis Averianov and Sues, 2007
Cenomanian, Late Cretaceous
Dzharakuduk Formation, Uzbekistan
Holotype- (ZIN PH 944/16) dentary, six teeth
Diagnosis- (after Averianov and Sues, 2007) distinguished from Troodon, Saurornithoides, Sinornithoides, Sinovenator, Sinusonasus and IGM 100/44 by the absence of serrations on the teeth; from Byronosaurus by the presence of fewer neurovascular foramina in the lateral groove on the dentary and by more bulbous anterior dentary crowns; from Mei by much larger size.
Comments- The holotype was discovered on September 9 2004.
Reference- Averianov and Sues, 2007. A new troodontid (Dinosauria: Theropoda) from the Cenomanian of Uzbekistan, with a review of troodontid records from the territories of the former Soviet Union. Journal of Vertebrate Paleontology. 27(1), 87-98.
U? sp. (Averianov and Sues, 2007)
Late Turonian, Late Cretaceous
Bissekty Formation, Uzbekistan
Material- (CCMGE 2/11822) tooth (Nessov, 1995)
(CCMGE 71/12455) premaxillary tooth (Nessov, 1993)
?(CCMGE 466/12457) partial braincase (Nessov, 1995)
?(CCMGE 475/12457) mid caudal vertebra (Nessov, 1995)
?(SPbGU VZ Din 7/2) incomplete posterior dorsal vertebra (23.4 mm) (Averianov and Sues, 2016)
?(USNM 538124) distal caudal vertebra (29 mm) (Averianov and Sues, 2016)
?(ZIN PH 99/16) pedal phalanx II-2 (Averianov and Sues, 2016)
(ZIN PH 265/16) anterior dentary tooth (Averianov and Sues, 2007)
?(ZIN PH 893/16) incomplete posterior dorsal vertebra (26.6 mm) (Averianov and Sues, 2016)
(ZIN PH 1899/16) posterior maxillary or dentary tooth (Averianov and Sues, 2007)
?(ZIN PH 2308/16) partial maxilla (Averianov and Sues, 2016)
?(ZIN PH 2339/16) incomplete anterior dorsal vertebra (27.7 mm) (Averianov and Sues, 2016)?
?(ZIN PH 2340/16) incomplete distal caudal vertebra (38 mm) (Averianov and Sues, 2016)
?(ZIN PH 2341/16) distal metatarsal III (Averianov and Sues, 2016)
?(ZIN PH 2342/16) distal metatarsal III (Averianov and Sues, 2016)
?(ZIN PH 2343/16) manual phalanx I-1 (43 mm) (Averianov and Sues, 2016)
?(ZIN PO 4608) partial dentary (Nessov, 1992)
? cervical vertebrae, metacarpal I (Averianov and Sues, 2007)
Comments- Nessov (1992, 1997) identified ZIN PO 4608 as an ichthyornithine. Nessov (1993, 1997) identified CCMGE 71/12455 as Deinonychosauria or Mammalia. Nessov (1995) identified CCMGE 2/11822 as Theropoda indet., CCMGE 466/12457 as possibly dromaeosaurid, and CCMGE 475/12457 as possibly ornithomimid. Averianov and Sues (2007) reidentified these and additional specimens as being troodontid, assigned to Urbacodon sp. due to the resemblence of the dental and dentary remains to the U. itemirensis holotype. The material was described in depth by Averianov and Sues (2016), except for the braincase CCMGE 466/12457 which will be described in a future publication on troodontid endocrania. Using a reweighted version of the TWiG analysis, the authors recovered Urbacodon as sister to Gobivenator outside Troodontinae.
References- Nessov, 1981. Cretaceous salamanders and frogs of the Kyzylkum Desert. Trudy Zoologicheskogo Instituta AN SSSR. 101, 57-88.
Nessov, 1992. Review of localities and remains of Mesozoic and Paleogene birds of the USSR and the description of new finds. Russkii Ornitologicheskii Zhurnal. 1, 7-50.
Nessov, 1993. New Mesozoic mammals of Middle Asia and Kazakhstan and comments about evolution of theriofaunas of the Cretaceous coastal plains of Asia. Trudy Zoologicheskogo Instituta RAN. 249, 105-133.
Nessov, 1995. Dinosaurs of northern Eurasia: New data about assemblages, ecology, and paleobiogeography. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University, St. Petersburg. 1-156.
Nessov, 1997. Cretaceous nonmarine vertebrates of northern Eurasia. Izdatelstvo Sankt-Peterburgskogo Universiteta, Saint Petersburg. 218 pp.
Averianov and Sues, 2007. A new troodontid (Dinosauria: Theropoda) from the Cenomanian of Uzbekistan, with a review of troodontid records from the territories of the former Soviet Union. Journal of Vertebrate Paleontology. 27(1), 87-98.
Averianov and Sues, 2016. Troodontidae (Dinosauria: Theropoda) from the Upper Cretaceous of Uzbekistan. Cretaceous Research. 59, 98-110.

Troodontinae Gilmore, 1924 vide Martyniuk, 2012
Definition- (Troodon formosus + Saurornithoides mongoliensis) (Martyniuk, 2012)
Other definitions- (Gobivenator mongoliensis + Zanabazar junior) (van der Reest and Currie, 2017)
(Sinovenator changii + Troodon formosus) (Hendrickx, Mateus, Araújo and Choiniere, 2019)
(Troodon formosus + Zanabazar junior + Gobivenator mongoliensis, - Sinovenator changii, Jinfengopteryx elegans) (modified after Kubota, Kobayashi and Ikeda, 2024)
= Saurornithoidinae Barsbold, 1974 vide Martyniuk, 2012
Comments- Martyniuk (2012) used three troodontid subfamilies, Jinfengopteryginae, Troodontinae and Saurornithoidinae, but did not define the latter. If ICZN rules are followed so that a subfamily cannot contain a subfamily, Saurornithoidinae cannot exist given Saurornithoides is an internal specifier of Troodontinae. van der Reest and Currie's (2017) more inclusive definition of Troodontinae is invalid as it does not include Troodon, the eponymous genus (Phylocode Article 11.7). Hendrickx et al.'s (2019) definition includes all troodontids except anchiornithines if they belong here instead of as archaeopterygids, and is unlikely to catch on if Sinovenatorinae is used.
References- Martyniuk, 2012. A Field Guide to Mesozoic Birds and Other Winged Dinosaurs. Pan Aves. 189 pp.
van der Reest and Currie, 2017. Troodontids (Theropoda) from the Dinosaur Park Formation, Alberta, with a description of a unique new taxon: Implications for deinonychosaur diversity in North America. Canadian Journal of Earth Sciences. 54, 919-935.
Hendrickx, Mateus, Araújo and Choiniere, 2019. The distribution of dental features in non-avian theropod dinosaurs: Taxonomic potential, degree of homoplasy, and major evolutionary trends. Palaeontologia Electronica. 22.3.74, 1-110.
Kubota, Kobayashi and Ikeda, 2024. Early Cretaceous troodontine troodontid (Dinosauria: Theropoda) from the Ohyamashimo Formation of Japan reveals the early evolution of Troodontinae. Scientific Reports. 14:16392.

"Saurornitholestes" robustus Sullivan, 2006
Late Campanian, Late Cretaceous
De-na-zin Member of the Kirtland Formation, New Mexico, US
Holotype- (SMP VP-1955) frontal (62 mm) (Sullivan, 2006)
Referred- ?(NMMNH P-68396) tooth (4.8x5.5x2.9 mm) (Williamson and Brusatte, 2014)
Diagnosis- Provisionally indeterminate relative to Troodon formosus, and incomparable to Talos.
Other diagnoses- Sullivan (2006) used the ratio of length (measured along the midline) to thickness (posterior part of the frontal) being 6:1 to distinguish robustus from S. langstoni, but this matches the condition in Troodon formosus once wear in robustus is accounted for.
Comments- Discovered in summer 2005, Sullivan (2006) originally described the frontal as a new species of the dromaeosaurid Saurornitholestes, distinguished from S. langstoni by its greater thickness. Turner et al. (2012) stated the holotype lacks the synapomorphies of Saurornitholestes, but listed no characters of that genus. They instead placed it as Theropoda indet.. Evans et al. (2014) reexamined the specimen and determined it was nearly identical to Troodon and indeterminate among derived troodontids. The tooth was said to fall within the range of variation of Dinosaur Park Troodon teeth by Williamson and Brusatte (2014).
References- Williamson, 2001. Dinosaurs from microvertebrate sites in the Upper Cretaceous Fruitland and Kirtland Formations, San Juan Basin, New Mexico. 2001 GSA abstracts.
Sullivan, 2006. Saurornitholestes robustus, n. sp. (Theropoda: Dromaeosauridae) from the Upper Cretaceous Kirtland Formation (De-na-zin Member), San Juan Basin, New Mexico. In Lucas and Sullivan (eds.). Late Cretaceous vertebrates from the Western Interior. New Mexico Museum of Natural History and Science Bulletin. 35, 253-256.
Turner, Makovicky and Norell, 2012. A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American Museum of Natural History. 371, 206 pp.
Evans, Larson, Cullen and Sullivan, 2014. 'Saurornitholestes' robustus is a troodontid (Dinosauria: Theropoda). Canadian Journal of Earth Sciences. 51(7), 730-734.
Larson, Cullen, Todd and Evans, 2014. Geometric morphometrics of small theropod frontals from the Dinosaur Park Formation, Alberta. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 165.
Williamson and Brusatte, 2014. Small theropod teeth from the Late Cretaceous of the San Juan Basin, northwestern New Mexico and their implications for understanding Latest Cretaceous dinosaur evolution. PLoS ONE. 9(4), e93190.

Troodontinae indet. (Lambe, 1902)
Late Campanian-Maastrichtian, Late Cretaceous
Judith River or Horseshoe Canyon Formation, Alberta, Canada
(RTMP 81.16.321) anterior dentary tooth (6 mm) (Currie, 1987)
(RTMP 81.20.71) anterior premaxillary tooth (Currie, 1987)
(RTMP 82.20.47) posterior dentary tooth (Currie, 1987)
(RTMP 82.20.299) mid-dentary tooth (Currie, 1987)
(RTMP 84.168.5) maxillary tooth (Currie, 1987)
Late Campanian-Maastrichtian, Late Cretaceous
Judith River or Edmonton Group, Alberta, Canada
(CMN 1266) tooth (Lambe, 1902)
(CMN 1560) astragalus (Zanno et al., 2011)
(CMN 8841) tooth (Sternberg, 1945)
(CMN coll.) five teeth (Sternberg, 1945)
Late Cretaceous
US
(AMNH 21629) tooth (AMNH online)
(YPM 55009) (YPM online)
(YPM 55040) (YPM online)
Comments- These could be Troodon, Stenonychosaurus, Latenivenatrix, Talos or another taxon.
References- Lambe, 1902. New genera and species from the Belly River Series (mid-Cretaceous). Contributions to Canadian Palaeontology, Geological Survey of Canada. 3, 23-81.
Sternberg, 1945. Pachycephalosauridae proposed for domeheaded dinosaurs, Stegoceras lambei n. sp., described. Journal of Paleontology. 19, 534-538.
Currie, 1987. Bird-like characteristics of the jaws and teeth of troodontid theropods (Dinosauria, Saurischia). Journal of Vertebrate Paleontology. 7, 72-81.
Zanno, Varricchio, O’Connor, Titus and Knell, 2011. A new troodontid theropod, Talos sampsoni gen. et sp. nov., from the Upper Cretaceous western interior basin of North America. PLoS ONE. 6(9), e24487.

undescribed Troodontidae (Eaton, Kirkland, Hutchison, Denton, O'Neill and Parrish, 1997)
Late Cenomanian, Late Cretaceous
Naturita Formation (= "Dakota Formation"), Utah, US
Material- (MNA or OMNH coll.) teeth
Comments- These are identified as cf. Troodon sp. indet. in Eaton et al. (1997) and later references.
References- Eaton, Kirkland, Hutchison, Denton, O'Neill and Parrish, 1997. Nonmarine extinction across the Cenomanian-Turonian boundary, southwestern Utah, with a comparison to the Cretaceous-Tertiary extinction event. Geological Society of America Bulletin. 109(5), 560-567.
Kirkland, Britt, Burge, Carpenter, Cifelli, DeCourten, Eaton, Hasiotis and Lawton, 1997. Lower to Middle Cretaceous dinosaur faunas of the central Colorado plateau: A key to understanding 35 million years of tectonics, sedimentology, evolution, and biogeography. Brigham Young University Geology Studies. 42, 69-103.

unnamed possible Troodontinae (Schwimmer, Sanders, Erickson and Weems, 2015)
Middle Campanian, Late Cretaceous
Coachman Formation, South Carolina, US
Material- (ChM PV8689) tooth (3 mm)
(ChM PV9111) incomplete tooth
Comments- These were only assigned to Theropoda indet. by Schwimmer et al. (2015), but the large serration size, particularly on the mesial carina, suggests they belong to troodontines.
Reference- Schwimmer, Sanders, Erickson and Weems, 2015. A Late Cretaceous dinosaur and reptile assemblage from South Carolina, USA. Transactions of the American Philosophical Society. 105(2), 157 pp.

unnamed possible troodontine (Rodriguez de la Rosa, 1996)
Early Maastrichtian, Late Cretaceous
Cañon del Tule Formation, Mexico
Material- (IGM-7710) pedal phalanx II-2 (22.5 mm)
Diagnosis- shaft more elongate than other troodontids; proximoventral heel bifurcated.
Comments- Although described as being from the Cerro del Pueblo Formation, Aguillon Martinez (2010) found this and other material from the El Pelillal locality belong to the later Cañon del Tule Formation.
Rodriguez de la Rosa and Cevallos-Ferriz (1998) refer this to the Troodontidae because the collateral ligament pit is centrally placed. This is only seen in Saurornithoides and Troodon though, not more basal forms (IGM 100/44, Sinornithoides, Borogovia). Thus IGM-7710 may be more closely related to the former two genera. Evans et al. (2014) believe this may belong to a turtle instead.
References- Hernandez, Aguillon, Delgado and Gomez, 1995. The Mexican Dinosaur National Monument. Journal of Vertebrate Paleontology. 15(3), 34A.
Rodriguez de la Rosa, 1996. Vertebrate remains from a Late Cretaceous locality (Campanian, Cerro del Pueblo Formation), Coahuila, Mexico. Journal of Vertebrate Paleontology. 16(3), 60A.
Rodriguez de la Rosa and Cevallos-Ferriz, 1998. Vertebrates of the El Pelillal locality (Campanian, Cerro del Pueblo Formation), southeastern Coahuila, Mexico. Journal of Vertebrate Paleontology. 18(4), 751-764.
Aguillon Martinez, 2010. Fossil vertebrates from the Cerro del Pueblo Formation, Coahuila, Mexico, and the distribution of Late Campanian (Cretaceous) terrestrial vertebrate faunas. MS thesis, Dedman College Southern Methodist University. 135 pp.
Evans, Larson, Cullen and Sullivan, 2014. 'Saurornitholestes' robustus is a troodontid (Dinosauria: Theropoda). Canadian Journal of Earth Sciences. 51(7), 730-734.

unnamed possible troodontine (Zinke, 1998)
Early Kimmeridgian, Late Jurassic
Alcobaca Formation, Portugal
Material- (IPFUB GUI D 93-97, 100, 102, 104, 111, 114-116, 156, 190) 14 teeth (~1.02 mm; FABL ~.92 mm)
Comments- These teeth can be identified as troodontid based on their constricted roots, enlarged serrations and hooked distal serrations. The latter are particularily derived characters among troodontids, as is the presence of serrations on most mesial teeth.
Reference- Zinke, 1998, Small theropod teeth from the Upper Jurassic coal mine of Guimarota (Portugal). Palaontologische Zeischrift. 72(1/2), 179-189.

unnamed Troodontinae (Averianov and Sues, 2007)
Early Santonian, Late Cretaceous
Yalovach Formation, Tajikistan
Material- (ZIN PH 1/66) anterior dentary tooth
(ZIN PH 2/66) dentary fragment
(ZIN PH 3/66) anterior dentary tooth
(ZIN PH 4/66) anterior maxillary tooth
(ZIN PH 5/66) posterior maxillary tooth
(ZIN PH 7/66) posterior dentary tooth
(ZIN PH 8/66) premaxillary tooth
?(ZIN PH 13/60) tooth
(ZIN PH coll.) at least four teeth
Comments- ZIN PH 13/60 may belong to another taxon because it is unserrated. The dentary fragment ZIN PH 2/66 lacks tooth crowns, so may be referrable to the taxon with serrated teeth or the same one as ZIN PH 13/60.
Reference- Averianov and Sues, 2007. A new troodontid (Dinosauria: Theropoda) from the Cenomanian of Uzbekistan, with a review of troodontid records from the territories of the former Soviet Union. Journal of Vertebrate Paleontology. 27(1), 87-98.

unnamed troodontine (Nessov and Golovneva, 1990)
Middle Maastrichtian, Late Cretaceous
Kakanaut Formation, Russia
Material- (ZIN PH 1/28) partial tooth
Diagnosis- (after Averianov and Sues, 2007) no distinct pits between the bases of the distal serrations; larger serrations (1.64/mm) than T. formosus.
Comments- This was referred to cf. Troodon sp. by Nessov and Goloneva (1990) and Nessov (1992), and Troodon cf. formosus by Averianov and Sues (2007) because Troodon is known from the Maastrichtian of Alaska, but the mesial carina is missing so it is unknown if serrations existed mesially.
References- Nessov and Golovneva, 1990. [History of the flora, vertebrates and climate in the late Senonian of the north-eastern Koriak uplands]. In Krasilov (ed.). [Continental Cretaceous of the USSR]. Dal’nevostochnoe Otdelenie AN SSSR. 191-212.
Nesov, 1992. Maastrichtian dinosaurs of NE Asia and climate changes caused by vertical oceanic circulation. International Conference on Arctic Margins, Abstracts. 43.
Averianov and Sues, 2007. A new troodontid (Dinosauria: Theropoda) from the Cenomanian of Uzbekistan, with a review of troodontid records from the territories of the former Soviet Union. Journal of Vertebrate Paleontology. 27(1), 87-98.

undescribed Troodontidae (Bolotsky and Moiseenko, 1988)
Late Maastrichtian, Late Cretaceous
Udurchukan Formation of the Tsagayan Group, Russia
Material- teeth
Comments- These teeth have been noted as Troodontidae indet. (Bolotsky and Moiseenko, 1988; Nessov and Golovneva, 1990; Nessov, 1995), Troodon cf. formosus (Moiseenko et al., 1997) and Troodon sp. (Alifanov and Bolotsky, 2002), but have yet to be described.
References- Bolotsky and Moiseenko, 1988. [On Dinosaurs of the Amur river region]. Amur KNII DVO AN SSSR. 38 pp.
Nessov and Golovneva, 1990. [History of the flora, vertebrates and climate in the late Senonian of the north-eastern Koriak uplands]. In Krasilov (ed.). [Continental Cretaceous of the USSR]. Dal’nevostochnoe Otdelenie AN SSSR. 191-212.
Nessov, 1995. Dinosaurs of nothern Eurasia: New data about assemblages, ecology, and paleobiogeography. Institute for Scientific Research on the Earth's Crust. 156 pp.
Moiseenko, Sorokin and Bolotsky, 1997. [Fossil reptiles of the Amur river area.] Amurskii Nauchnyi Tsentr DVO RAN. 54 pp.
Alifanov and Bolotsky, 2002. New data about the assemblages of the Upper Cretaceous carnivorous dinosaurs (Theropoda) from the Amur region. In Kirillova (ed.). Fourth International Symposium of IGCP 434. 25-26.
Averianov and Sues, 2007. A new troodontid (Dinosauria: Theropoda) from the Cenomanian of Uzbekistan, with a review of troodontid records from the territories of the former Soviet Union. Journal of Vertebrate Paleontology. 27(1), 87-98.

undescribed Troodontidae (Currie and Eberth, 1993)
Middle-Late Campanian, Late Cretaceous
Erenhot, Iren Dabasu Formation, Inner Mongolia, China
Material- (AMNH 6570 in part; paratype of Ornithomimus asiaticus) (juvenile or subadult) axis, third cervical vertebra, fifth cervical vertebra (Makovicky, 1995)
?(AMNH 6576 in part; paratype of Ornithomimus asiaticus) pedal ungual I (~17 mm) (pers. obs.)
(AMNH 21751) distal metatarsals III (Currie and Eberth, 1993)
(AMNH 21772) metatarsal II (~183 mm) (Currie and Eberth, 1993)
(AMNH 25570) three vertebrae (AMNH online)
(AMNH 30261) proximal metatarsal (AMNH online)
(AMNH 30262) proximal tibial fragment (AMNH online)
(AMNH 30263) proximal tibial fragment (AMNH online)
(AMNH 30264) tibial fragment, fibular fragment (AMNH online)
(AMNH 30265) proximal tibia (AMNH online) 142
(AMNH 30266) proximal fibula (AMNH online) 142
(AMNH 30267) proximal tibia (AMNH online)
(AMNH 30268) proximal fibula (AMNH online)
(AMNH 30269) proximal fibula (AMNH online) 142
(AMNH 30270) proximal fibula (AMNH online)
(AMNH 30271) partial astragalus (AMNH online)
(AMNH 30272) partial astragalus (AMNH online)
(AMNH 30273) partial astragalus (AMNH online)
(AMNH 30274) partial astragalus (AMNH online)
(AMNH 30275) distal humerus (AMNH online)
(AMNH 30276) distal humerus (AMNH online)
(AMNH 30277) distal humerus (AMNH online)
(AMNH 30278) proximal humerus (AMNH online)
(AMNH 30279) proximal humerus (AMNH online)
(AMNH 30280) proximal ulna (AMNH online)
(AMNH 30281) distal radius (AMNH online)
(AMNH 30282) distal radius (AMNH online)
(AMNH 30283) proximal scapula (AMNH online)
(AMNH 30284) proximal scapula (AMNH online)
(AMNH 30285) scapular blade (AMNH online)
(AMNH 30286) pedal ungual I (~19 mm) (AMNH online)
(AMNH 30287) proximal manual ungual (AMNH online)
(AMNH 30288) two posterior cervical or proximal caudal vertebrae (AMNH online)
(AMNH 30289) distal metatarsal IV (AMNH online)
(AMNH 30290) distal metatarsal IV (AMNH online)
(AMNH 30291) distal metatarsal IV (AMNH online)
(AMNH 30292) distal metatarsal III (AMNH online)
(AMNH 30293) distal metatarsal III (AMNH online)
(AMNH 30294) distal metatarsal II (AMNH online)
(AMNH 30295) distal metatarsal II (AMNH online)
(AMNH 30296) distal metatarsal II (AMNH online)
(AMNH 30297) distal metatarsal II (AMNH online)
(AMNH 30300) partial ilium (AMNH online) 142
(AMNH 30301) proximal ?pubis (AMNH online) 142
(AMNH 30302) ?ilial fragment (AMNH online)
(AMNH 30303) partial synsacrum (AMNH online) 142
(AMNH 30304) proximal ?pubis (AMNH online)
?(AMNH 30305) last sacral vertebra (~25 mm) (AMNH online)
(AMNH 30306) partial synsacrum (AMNH online)
(AMNH 30307) synsacral fragment(AMNH online)
(AMNH 30308) partial posterior cervical vertebra (AMNH online)
(AMNH 30309) partial posterior cervical vertebra (AMNH online)
(AMNH 30310) partial anterior dorsal vertebra (AMNH online)
(AMNH 30311) partial anterior dorsal vertebra (AMNH online)
(AMNH 30312) partial anterior dorsal centrum (AMNH online)
(AMNH 30313) incomplete anterior dorsal centrum (AMNH online)
(AMNH 30314) partial anterior dorsal centrum (AMNH online)
(AMNH 30315) incomplete anterior dorsal centrum (AMNH online)
(AMNH 30316) partial anterior dorsal vertebra (AMNH online)
(AMNH 30317) incomplete anterior dorsal centrum (~24 mm) (AMNH online)
(AMNH 30318) anterior dorsal centrum (~26 mm) (AMNH online)
(AMNH 30320) anterior dorsal centrum (~26 mm) (AMNH online) 142
(AMNH 30321) partial anterior dorsal vertebra (~26 mm) (AMNH online)
?(AMNH 30322) anterior dorsal centrum (~32 mm) (AMNH online)
(AMNH 30323) incomplete posterior dorsal centrum (~22 mm) (AMNH online)
(AMNH 30324) incomplete dorsal centrum (AMNH online)
(AMNH 30325) posterior dorsal centrum (~26 mm) (AMNH online)
(AMNH 30326) posterior dorsal centrum (~27 mm) (AMNH online)
(AMNH 30327) posterior dorsal centrum (~27 mm) (AMNH online)
(AMNH 30328) incomplete posterior dorsal vertebra (~27 mm) (AMNH online)
(AMNH 30329) incomplete posterior dorsal vertebra (~29 mm) (AMNH online)
(AMNH 30330) proximal caudal centrum (~23 mm) (AMNH online)
(AMNH 30336) ?central fragment (AMNH online)
(AMNH 30337) incomplete distal caudal vertebra (~35 mm) (AMNH online)
(AMNH 30338) mid caudal vertebra (~32 mm) (AMNH online)
(AMNH 30339) incomplete mid caudal vertebra (~31 mm) (AMNH online)
(AMNH 30340) incomplete mid caudal vertebra (AMNH online)
(AMNH 30341) partial distal caudal vertebra (AMNH online)
(AMNH 30342) mid caudal vertebra (~29 mm) (AMNH online)
(AMNH 30343) mid caudal vertebra (~30 mm) (AMNH online)
(AMNH 30344) distal caudal vertebra (~32 mm) (AMNH online)
(AMNH 30345) incomplete mid caudal vertebra (~25 mm) (AMNH online)
(AMNH 30346) partial distal caudal vertebra (AMNH online)
(AMNH 30347) partial distal caudal vertebra (AMNH online)
(AMNH 30348) distal caudal vertebra (~31 mm) (AMNH online)
(AMNH 30349) fragmentary distal caudal vertebra (AMNH online)
(AMNH 30350) distal caudal vertebra (~33 mm) (AMNH online)
(AMNH 30351) incomplete distal caudal vertebra (~31 mm) (AMNH online)
(AMNH 30352) partial distal caudal vertebra (AMNH online)
(AMNH 30353) incomplete distal caudal vertebra (AMNH online)
(AMNH 30354) distal caudal vertebra (~23 mm) (AMNH online)
?(AMNH 30355) mid caudal vertebra (~32 mm) (AMNH online)
(AMNH 30356) proximal caudal centrum (~28 mm) (AMNH online)
(AMNH 30357) incomplete proximal caudal vertebra (~25 mm) (AMNH online)
(AMNH 30358) proximal caudal vertebra (~24 mm) (AMNH online)
(AMNH 30359) incomplete proximal caudal centrum (AMNH online)
(IVPP 230790-16; = IVPP 230090-16 of Currie and Eberth, 1993) metatarsal III (Currie and Eberth, 1993)
Comments- Currie and Eberth (1993) stated "Troodontid bones are rare, but include distinctive third metatarsals (AMNH 21751, 21772, IVPP 230090-16), in which the distal articulation extends onto the posterior surfrace of the bone in a broad tongue." However, Currie and Dong (2001) corrected the identification of the second specimen, stating "AMNH 21772 is the proximal end of a second metatarsal. It is identified as a troodontid on the basis of its contact surface for the fourth metatarsal, its size, and especially its lateromedial compression." The AMNH online catalogue photo indicates most of the element is preserved and the locality info is "8 mi. E. of station" indicating it was found in localities 140-149 in 1923 or 1928. Currie and Dong describe AMNH 21751 as "two distal ends of third metatarsals [that] are about the same size and represent left and right elements. Although they may represent the same individual, the two fossils are different colours, which suggests they may not have been found together." They indicate these were "Collected in the 1920s by the third Central Asiatic Expedition from exposures of the Iren Dabasu Formation (?Santonian) near Erenhot." Currie and Dong list IVPP 230790-16 (presumably the correct field number for Currie and Eberth's 'IVPP 230090-16') as a metatarsal "Collected in 1990 from exposures of the Iren Dabasu Formation (?Santonian) near Erenhot", which would make it found during the second Sino-Canadian expedition. They state "the tongue-like extensions of the third metatarsals from Iren Dabasu are flat like those of Troodon ... , Borogovia ... , and Tochisaurus" but unlike the grooved surface of Sinornithoides or the distally restricted surface of Philovenator. This has since been identified in Bissekty Urbacodon sp. ZIN PH 2342/16, and it should be noted the extension of Tochisaurus is much shorter, while Mei, IGM 100/44, 100/140 and 100/1126 have a condition like Sinornithoides. Thus as hypothesized by Dong and Currie, at least AMNH 21751 and IVPP 230790-16 are closer to Troodon than Sinornithoides. Currie and Eberth stated "These bones are provisionally referred to Saurornithoides" (at the time a concept including Zanabazar) without rationale, but Currie and Dong instead classified them as "an unknown species of troodontid", stating they "cannot be identified further without additional material."
Makovicky (1995) stated "A probable troodontid axis (AMNH 6570), articulated with a third cervical vertebra, is present in the collections of the American Museum of Natural History. This identification is based on the morphology of the associated third cervical and a probable fifth cervical, possibly from the same individual, which strongly resembles those of Troodon. The axis is from an immature individual as seen from absence of both the odontoid and axial intercentrum." This specimen number includes over two hundred paratype Archaeornithomimus elements from the Kaisen Quarry AMNH locality 140, and the cervicals described were not recognized in the material catalogued under it in July 2009 (pers. obs.). However, a small ungual was noticed in AMNH 6576 (which includes almost a hundred paratype Archaeornithomimus elements from the Johnson Quarry AMNH locality 141) that most closely resembles a troodontid pedal ungual I in the slight curvature, proximally placed flexor tubercle and posterodorsal extent being less than its posteroventral extent.
The AMNH online catalogue lists AMNH 25570 as "Troodon ?", consisting of "3 vertebrae." A large number of elements (AMNH 30261-30297, 30300-30318, 30320-30330, 30336-30359) are labeled are labeled "Troodontid" on the AMNH online catalogue, each from the same location ("8 mi. E. of station") and from AMNH Quarry 142 specifically when visible in the photo (AMNH 30265, 30266, 32069, 30300, 30301, 30303, 30320). Given the similar preservation and number of elements preserved, it is possible these represent two individuals, and that several other specimens only identified to the level of Saurischia in the online catalogue (AMNH 30245, 30247-30260, 30298-30299, 30360) that are also from "8 mi. E. of station" may belong to them as well. Note AMNH 30267 is incorrectly identified as a proximal fibula, while 30288 is called "Proximal end of metatarsal IV" but seems to be two vertebrae instead, AMNH 30301 is called an "Ilium fragment." but may be a proximal pubis (posterior edge downward in photo), AMNH 30302 is labeled as "Acetabulum fragment." and indeed may be the ischial peduncle and postacetabular base of a left ilium, AMNH 30304 is labeled "Prox. end of ischium" but more closely resembles a proximal troodontid pubis in the diverging peduncles and shallowly concave acetabular edge, AMNH 30305 is a last sacral vertebra with a convex posterior central face and 30322 is an anterior dorsal with convex anterior central face so both may be alvarezsaurid instead. Scoring the material as photographed in the online catalogue (with AMNH 30305 and 30322 excluded, and 30301 and 30304 interpreted as pubes) into Hartman et al.'s maniraptoromorph matrix does result in it being troodontid, but note examination of the specimens themselves would provide far more data for each element and that it's currently only an assumption that they belong to the same taxon.
References- Currie and Eberth, 1993. Palaeontology, sedimentology and palaeoecology of the Iren Dabasu Formation (Upper Cretaceous), Inner Mongolia, People's Republic of China. Cretaceous Research. 14, 127-144.
Makovicky, 1995. Phylogenetic aspects of the vertebral morphology of Coelurosauria (Dinosauria: Theropoda). Masters thesis, University of Copenhagen. 311 pp.
Currie and Dong, 2001. New information on Cretaceous troodontids (Dinosauria, Theropoda) from the People's Republic of China. Canadian Journal of Earth Sciences. 38(12), 1753-1766.
Averianov and Sues, 2012. Correlation of Late Cretaceous continental vertebrate assemblages in middle and central Asia. Journal of Stratigraphy. 36(2), 462-485.

unnamed possible troodontid (Mathur and Srivastava, 1987)
Maastrichtian, Late Cretaceous
Lameta Formation, India
Material- (GSI 19996) tooth (7x4x2 mm)
Comments- This was described by Mathur and Srivastava (1987) as (?) Megalosaurus type E. It was listed under Troodontidae by Ford (online 2015). The tooth is strongly recurved and short with subequal (10 per 5 mm), blunt serrations on the mesial and distal carinae, absent apically. It differs from Kallamedu Formation tooth DUGF/52 in being narrower, with a more concave distal edge and serrations absent apically.
References- Mathur and Srivastava, 1987. Dinosaur teeth from Lameta Group (Upper Cretaceous) of Kheda District, Gujarat. Journal of the Geological Society of India. 29, 554-566.
Ford, online 2015. http://www.paleofile.com/Dinosaurs/Theropods/Troodonincertae.asp

unnamed troodontid (Goswami, Prasad, Benson, Verma and Flynn, 2012)
Late Maastrichtian, Late Cretaceous
Kallamedu Formation, India
Material- (DUGF/52) tooth (3.5 x 2.8 mm)
References- Goswami, Prasad, Benson, Verma and Flynn, 2012. New vertebrates from the Late Cretaceous Kallamedu Formation, Cauvery basin, south India, including a troodontid dinosaur, a gondwanatherian mammal, and a Simosuchus-like notosuchian crocodyliform. Journal of Vertebrate Paleontology. Program and Abstracts 2012, 102.
Goswami, Prasad, Verma, Flynn and Benson, 2013. A troodontid dinosaur from the latest Cretaceous of India. Nature Communications. 4, 1703.

Borogovia Osmólska, 1987
B. gracilicrus Osmólska, 1987
Early Maastrichtian, Late Cretaceous
Altan Uul IV, Nemegt Formation, Mongolia
Holotype- (ZPAL MgD-I/174) incomplete tibiotarsi (27 mm wide distally), proximal fibula, distal metatarsals II, phalanges II-1 (32 mm), phalanges II-2 (13 mm), pedal unguals II (31 mm), distal metatarsal III, distal phalanges III-1, phalanx III-2 (23 mm), phalanges III-3 (22 mm), pedal ungual III (15 mm), distal metatarsals IV, phalanges IV-1 (18 mm), phalanges IV-2 (17 mm), phalanges IV-3 (15 mm), phalanges IV-4 (16 mm), pedal unguals IV (21.5 mm; one distal)
Diagnosis- (after Osmólska, 1987) very slender and long tibiotarsus; second toe with very short phalanx II-2 and straight ungual; third toe much thinner and weaker than the second and fourth toes.
Comments- This specimen was discovered in 1971 and first mentioned by Osmólska (1982) as "personal observation on Saurornithoides sp. in the ZPAL collection" and "ZPAL Saurornithoides
sp. specimen from the Nemegt Formation of the Gobi Desert (personal observation)." It may be a junior synonym of Zanabazar as posited by Osmólska (1987), as the known material of the two doesn't overlap.
References- Osmólska, 1982. Hulsanpes perlei n.g.n.sp. (Deinonychosauria, Saurisichia, Dinosauria) from the Upper Cretaceous Barun Goyot Formation of Mongolia. Neües Jahrbuch fur Geologie und Palaontologie Monatschefte. 1982(7), 440-448.
Osmólska, 1987. Borogovia gracilicrus gen. et sp. n., a new troodontid dinosaur from the Late Cretaceous of Mongolia. Acta Palaeontologica Polonica. 32, 133-150.

Saurornithoides Osborn, 1924b
= "Ornithoides" Osborn, 1924a
S. mongoliensis Osborn, 1924b
= "Ornithoides oshiensis" Osborn, 1924a
= Troodon mongoliensis (Osborn, 1924b) Paul, 1988
Late Campanian, Late Cretaceous
Bayn Dzak, Djadokhta Formation, Mongolia
Holotype- (AMNH 6516) (1.56 m; 13 kg) incomplete skull (192 mm), three sclerotic plates, incomplete mandibles, ninth dorsal vertebra, tenth dorsal vertebra (23 mm), eleventh dorsal vertebra (22 mm), incomplete twelfth dorsal vertebra (23 mm), (sacrum 147 mm) incomplete first sacral vertebra (23 mm), partial second sacral centrum (24 mm), partial third sacral centrum (25 mm), partial fourth sacral centrum (25 mm), partial fifth sacral vertebra (25 mm), incomplete sixth sacral vertebra (25 mm), incomplete first caudal vertebra (22 mm), incomplete second caudal vertebra (23 mm), partial third caudal vertebra, partial fourth caudal vertebra, incomplete first chevron, partial second chevron, partial third chevron, ilial fragment, incomplete pubes, ischia (114 mm), proximal femur (~198 mm), tibial mold (~243 mm), metatarsal I fragments, phalanx I-1 (16 mm), incomplete pedal ungual I, partial metatarsal II, phalanx II-1 (27.5 mm), phalanx II-2 (14 mm), pedal ungual II (29.3 mm), distal metatarsal III (~139 mm), phalanx III-1 (~33 mm), phalanx III-2 (24 mm), proximal phalanx III-3, partial metatarsal IV, phalanx IV-1 (20.5 mm), proximal phalanx IV-2
Late Campanian, Late Cretaceous
Hermiin Tsav, Baruungoyot Formation, Mongolia
Referred- ?(IGM coll.; 970719 KmT AMRM-3) partial skeleton (Watabe and Suzuki, 2000)
Late Campanian, Late Cretaceous
Ukhaa Tolgod, Djadokhta Formation, Mongolia
?(IGM 100/1083) (1.85 m; 21 kg) maxillary fragment, incomplete quadrate, incomplete anterior cervical vertebra, partial anterior dorsal vertebra, sacral fragment, three distal caudal vertebrae, distal tarsal IV, pedal ungual II (34.7 mm), distal metatarsal III, proximal metatarsal IV, four pedal phalanges (Norell and Hwang, 2004)
Late Campanian, Late Cretaceous
Wulansuhai Formation (= Bayan Mandahu Formation), Inner Mongolia, China
?(IVPP V10599) partial sacrum, caudal vertebrae, chevrons, pelvis (Currie and Dong, 2001)
Diagnosis- More derived than Sinornithoides and Sinusonasus due to the absent promaxillary fenestra, large serrations on teeth, and six sacral vertebrae. Less derived than Zanabazar and Troodon due to the dorsal tympanic recess.
Other diagnoses- Osborn (1924b) was the first to publish a diagnosis, but as the specimen was the first troodontid known from more than teeth, the generic diagnosis is now far too generalized. The presence of five pairs of external cranial fenestrae is incorrect, as Osborn did not take the supratemporal fenestrae into account, but six pairs are primitive for tetanurines anyway. The external mandibular fenestra is primitive for archosaurs, while the fairly homodont maxillary series is primitive for an even more inclusive group. The presence of nineteen premaxillary and maxillary teeth is incorrect, as there are actually twenty-three. The "less raptorial" teeth are also found in other maniraptoriforms except dromaeosaurids. Teeth which have only distal serrations are also now known in several other troodontids (e.g. Sinornithoides, Sinusonasus, Zanabazar). Maxillary teeth which lack replacement gaps are also present in Mei, Sinovenator and basal avialans, so may be plesiomorphic. Of his listed "specific characters", the posteriorly increasing size of maxillary teeth, closely spaced dentary teeth, and teeth with a sub-acute tip are common in troodontids. The premaxillary teeth do not decrease in size posteriorly though, as the first tooth is small, the second unpreserved, and the third and fourth subequal (Norell et al., 2009). The illusion of decreasing size is due to the length of the roots which are exposed. Flattened, recurved teeth are primitive for archosaurs
Norell et al. (2009) listed several characters in their diagnosis, as they differ from Zanabazar. While Saurornithoides is smaller than Zanabazar, Norell et al. note all other named troodontids except perhaps Troodon are as well. Norell et al. also distinguish it from Zanabazar by its low tooth count (19 maxillary teeth and ~31-33 dentary teeth), but Sinornithoides (18 maxillary teeth), Sinusonasus (~19 maxillary teeth) and Urbacodon (32 dentary teeth) are similar. A jugal with a straight ventral edge below the front of the orbit is also present in Mei and seemingly Sinornithoides, and is somewhat uncertain in Saurornithoides due to breakage in any case. The dorsal tympanic recess is plesiomorphic, being present in Byronosaurus and Sinovenator as well. Norell et al. note their last listed character (maxillary teeth with only slight posterior increase in height) is also present in Mei, Sinovenator and basal avialans, so may be plesiomorphic.
Comments- The holotype was discovered on July 9 1923 and initially announced in a magazine article (Osborn, 1924a) as Ornithoides oshiensis, "a dinosaur birdlike in its skull form", "a name given in allusion to the fact that the reptile was found in the basin Oshih, with numerous teeth." A partial sacrum, three mid caudal vertebrae and two partial ilia were originally included in the holotype, but were reidentified as protoceratopsian by Norell et al. (2009) and placed in the new number AMNH 30613. Currie and Peng (1994) described hindlimb IVPP V10597 as a possible juvenile Saurornithoides mongoliensis, but this was made the holotype of Philovenator curriei by Xu et al. in 2012. Watabe and Suzuki (2000) mention "a Saurornithoides partial skeleton" found on July 18 1997 at Hermiin Tsav, given field number 970719 KmT AMRM-3. It has not been described yet but may belong to Harenadraco discovered at the same locality 21 years later. Norell and Hwang (2004) described a fragmentary specimen found in 1993 they provisionally referred to Saurornithoides mongoliensis, as it was identical except for being larger. Norell et al. noted definitive referral was not possible, though they did state the tooth replacement was more similar to Saurornithoides than to Byronosaurus. IVPP V10599 was mentioned by Currie and Dong as being referrable to Saurornithoides mongoliensis and having a sixth sacral vertebra derived from the caudal series, but details including a rationale for the referral are lacking. It was discovered in 1988 as part of the Dinosaur Project, and may be referrable to the troodontines Papiliovenator or Linhevenator later described from the same formation.
References- Osborn, 1924a. The discovery of an unknown continent. Natural History. 24(2), 133-149.
Osborn, 1924b. Three new Theropoda, Protoceratops zone, central Mongolia. American Museum Novitates. 144, 1-12.
Russell, 1969. A new specimen of Stenonychosaurus from the Oldman Foramtion of Alberta. Canadian Journal of Earth Sciences. 6, 595-612.
Barsbold, 1974. Saurornithoididae, a new family of small theropod dinosaurs from Central Asia and North America. Palaeontologia Polonica. 30, 5-22.
Paul, 1988. Predatory Dinosaurs of the World. Simon and Schuster Co., New York. 464 pp.
Osmólska and Barsbold, 1990. Troodontidae. In Weishampel, Dodson, and Osmólska (eds). The Dinosauria, Berkeley: University of California Press. 259-268.
Currie and Peng, 1994. A juvenile specimen of Saurornithoides mongoliensis from the Upper Cretaceous of northern China. Canadian Journal of Earth Sciences. 30(10), 2224-2230.
Watabe and Suzuki, 2000. Report on the Japan - Mongolia Joint Paleontological Expedition to the Gobi desert, 1997. Hayashibara Museum of Natural Sciences Research Bulletin. 1, 69-82.
Currie and Dong, 2001. New information on Cretaceous troodontids (Dinosauria, Theropoda) from the People's Republic of China. Canadian Journal of Earth Sciences. 38(12), 1753-1766.
Norell and Hwang, 2004. A troodontid dinosaur from Ukhaa Tolgod (Late Cretaceous Mongolia). American Museum Novitates. 3446, 9 pp.
Norell, Makovicky, Bever, Balanoff, Clark, Barsbold and Rowe, 2009 online. Saurornithoides mongoliensis, Digital Morphology. http://digimorph.org/specimens/Saurornithoides_mongoliensis/
Norell, Makovicky, Bever, Balanoff, Clark, Barsbold and Rowe, 2009. A review of the Mongolian Cretaceous dinosaur Saurornithoides (Troodontidae: Theropoda). American Museum Novitates. 3654, 63 pp.

Zanabazar Norell, Makovicky, Bever, Balanoff, Clark, Barsbold and Rowe, 2009
= "Mongolodon" Franzosa, 2004
Z. junior (Barsbold, 1974) Norell, Makovicky, Bever, Balanoff, Clark, Barsbold and Rowe, 2009
= Saurornithoides junior Barsbold, 1974
= "Mongolodon" junior (Barsbold, 1974) Franzosa, 2004
Early Maastrichtian, Late Cretaceous
Bugin Tsav, Nemegt Formation, Mongolia
Holotype- (IGM 100/1) (2.28 m, 27 kg, adult) skull (280.6 mm), anterior mandibles, (sacrum- 200 mm) first sacral vertebra (~34 mm), second sacral vertebra (~31 mm), third sacral vertebra (31 mm), fourth sacral vertebra (31 mm), fifth sacral vertebra (36 mm), sixth sacral vertebra (36.2 mm), proximal caudal vertebra (~31.5 mm), proximal caudal vertebra (33 mm), proximal caudal vertebra (32 mm), proximal caudal vertebra (32 mm), proximal caudal vertebra (33 mm), proximal caudal vertebra (32.8 mm), mid caudal vertebra (31.5 mm), mid caudal vertebra (34 mm), mid caudal vertebra (37 mm), distal caudal vertebra (38 mm), distal caudal vertebra (38 mm), distal caudal vertebra (39 mm), distal caudal vertebra (39.5 mm), distal caudal vertebra (39.5 mm), two proximal chevrons, mid chevron, five distal chevrons, distal tibia (68 mm wide), astragalocalcaneum, distal tarsal III, distal tarsal IV, proximal metatarsal II, proximal metatarsal III, proximal metatarsal IV
Late Cretaceous
Mongolia
Referred- ?(IGM 100/2) postcrania (Barsbold, 1983)
Diagnosis- (after Norell et al., 2009) exoccipital forms large part of posttemporal fenestra (unknown in other troodontids except Troodon); deep paroccipital processes, with proximodorsal edge above foramen magnum.
Other diagnoses- Barsbold (1974) originally only listed "large Saurornithoides with 20 maxillary and 35 dentary teeth" in his diagnosis. The large size is also seen in Troodon. The maxillary tooth count (19-20) overlaps Saurornithoides (19) and Sinusonasus (~19), while the dentary tooth count (35) is the same as Troodon.
Norell et al. (2009) also listed several other characters in their diagnosis. The absent dorsal tympanic recess is shared with Troodon. They note the foramen magnum is more transversely compressed than Troodon, but that Byronosaurus and Sinovenator are similar, making it plesiomorphic. Similarly, the lack of a separate canal for the ophthalmic branch of the trigeminal nerve is also seen in Byronosaurus and most dromaeosaurids, meaning it is plesiomorphic as well.
Comments- The holotype was discovered in 1964 and initially described by Barsbold (1974)as a new species of Saurornithoides, from the earlier Djadochta Formation. Contrary to Barsbold, Norell et al. note the teeth lack mesial serrations, the caudal vertebrae are probably not a continuous series, and the distal fibula is unpreserved. However, they also fail to note three proximal caudal vertebrae in their materials list and description. Franzosa (2004) assigned this species to a new genus "Mongolodon" without comment in his unpublished thesis. However, Norell et al. (2009) later redescribed the species and made it the type of their new genus Zanabazar. This was largely done because of the absence of characters supporting a sister relationship with Saurornithoides mongoliensis, though Norell et al. do not explicitly support a closer relationship of either species to Troodon either. Borogovia may be a junior synonym (Osmólska, 1987), as its holotype cannot be compared to IGM 100/1. Tochisaurus is not a junior synonym however (Kurzanov and Osmólska, 1991), though this was proposed as possible by Osmólska.
Barsbold (1983) states "besides the holotype, remains of the postcranial skeleton of another specimen, no. 100/2" can be referred to the taxon, but it has not been mentioned in other references. Norell et al. (2009) even state "the holotype remains the only known specimen of this species" with Barsbold as a coauthor.
References- Barsbold, 1974. Saurornithoididae, a new family of small theropod dinosaurs from Central Asia and North America. Palaeontologia Polonica. 30, 5-22.
Barsbold, 1983. Carnivorous dinosaurs from the Cretaceous of Mongolia. Transactions of the Joint Soviet-Mongolian Paleontological Expedition. 19, 5-119.
Osmólska, 1987. Borogovia gracilicrus gen. et sp. n., a new troodontid dinosaur from the Late Cretaceous of Mongolia. Acta Palaeontologica Polonica. 32, 133-150.
Osmólska and Barsbold, 1990. Troodontidae. In Weishampel, Dodson, and Osmólska (eds.). The Dinosauria. University of California Press. 259-268.
Kurzanov and Osmólska, 1991. Tochisaurus nemegtensis gen. et sp. n., a new troodontid (Dinosauria, Theropoda) from Mongolia. Acta Palaeontologia Polonica. 36, 69-76.
Franzosa, 2004. Evolution of the Brain in Theropoda (Dinosauria). PhD Thesis. The University of Texas at Austin. 357 pp.
Norell, Makovicky, Bever, Balanoff, Clark, Barsbold and Rowe, 2009 online. Zanabazar junior, Digital Morphology. http://digimorph.org/specimens/Zanabazar_junior/
Norell, Makovicky, Bever, Balanoff, Clark, Barsbold and Rowe, 2009. A review of the Mongolian Cretaceous dinosaur Saurornithoides (Troodontidae: Theropoda). American Museum Novitates. 3654, 63 pp.

Papiliovenator Pei, Qin, Wen, Zhao, Wang, Liu, Guo, Liu, Ye, Wang, Yin, Dai and Xu, 2021
P. neimengguensis Pei, Qin, Wen, Zhao, Wang, Liu, Guo, Liu, Ye, Wang, Yin, Dai and Xu, 2021
Late Campanian, Late Cretaceous
Wulansuhai Formation, Inner Mongolia, China
Holotype- (BNMNH-PV030) (subadult) incomplete skull (~120 mm), incomplete mandible, hyoids, atlantal neural arch, axis, partial third cervical vertebra, partial fourth cervical vertebra, two fragmentary mid cervical vertebrae, partial eighth cervical vertebra, fragmentary ninth cervical vertebra, partial tenth cervical vertebra, incomplete first dorsal vertebra, second dorsal vertebra, incomplete third dorsal vertebra, partial fourth dorsal vertebra, few fragmentary dorsal ribs, partial scapulae, partial coracoid, incomplete humeri (~90 mm), incomplete radius, partial ulna, phalanx I-1, manual ungual I, phalanx II-1, fragmentary pelvis, incomplete femur, partial tibia, incomplete fibula, partial metatarsal II, incomplete phalanx II-1, partial phalanx II-2, pedal unguals II, incomplete metatarsal III, incomplete metatarsal IV
Diagnosis- (after Pei et al., 2021) lateral groove of dentary not posteriorly expanded; deep surangular fossa hosting the surangular foramen anteroventral to glenoid fossa; ventral ridge of surangular fossa mainly on surangular; anterolaterally broadened and butterfly-shaped neural arches of the first and second dorsal vertebrae in dorsal view.
Comments- This was discovered in 2018. Pei et al. (2021) used a version of the TWiG analysis to recover it as a troodontid sister to Byronosaurus, Gobivenator, Xixiasaurus and troodontines. In the Hartman et al. maniraptoromorph matrix it is the sister of Zanabazar, with a position similar to Pei et al.'s less parsimonious by two steps. Forcing it to be sister to Linhevenator or Philovenator from the same formation requires four more steps each.
Reference- Pei, Qin, Wen, Zhao, Wang, Liu, Guo, Liu, Ye, Wang, Yin, Dai and Xu, 2021 online. A new troodontid from the Upper Cretaceous Gobi basin of Inner Mongolia, China. Cretaceous Research. Journal Pre-proof. DOI: 10.1016/j.cretres.2021.105052

Troodon Leidy, 1856
?= Polyodontosaurus Gilmore, 1932
?= Stenonychosaurus Sternberg, 1932
?= Pectinodon Carpenter, 1982
?= Latenivenatrix van der Reest and Currie, 2017
T. formosus Leidy, 1856
?= Laelaps cristatus Cope, 1876
?= Dryptosaurus cristatus (Cope, 1876) Hay, 1902
?= Deinodon cristatus (Cope, 1876) Osborn, 1902 non (Marsh, 1892) Hay, 1902
?= Dromaeosaurus cristatus (Cope, 1876) Matthew and Brown, 1922
?= Polyodontosaurus grandis Gilmore, 1932
?= Stenonychosaurus inequalis Sternberg, 1932
?= Saurornithoides inequalis (Sternberg, 1932) Carpenter, 1982
= Stegoceras formosum (Leidy, 1856) Olshevsky, 1991
?= Troodon cristatus (Cope, 1876) Olshevsky, 1995
?= Troodon inequalis (Sternberg, 1932) Snively and Russell, 2002
?= Latenivenatrix mcmasterae van der Reest and Currie, 2017
Late Campanian, Late Cretaceous
Judith River Formation, Montana, US
Holotype- (ANSP 9259) posterior premaxillary tooth
Referred- (AMNH 3954; syntypes of Laelaps cristatus) two maxillary teeth (11 mm)
(AMNH 8519) tooth (Sahni, 1972)
(AMNH 8520) tooth (3.4 mm) (Sahni, 1972)
(AMNH 21760) tooth (AMNH online)
(ANSP 15937) dentary tooth (Fiorillo and Currie, 1994)
(ANSP 15947) maxillary tooth (Fiorillo and Currie, 1994)
(ANSP 15950) maxillary tooth (Fiorillo and Currie, 1994)
(ANSP 15964) dentary tooth (Fiorillo and Currie, 1994)
(ANSP 17642) premaxillary tooth (Fiorillo and Currie, 1994)
(ANSP 17780) premaxillary tooth (Fiorillo and Currie, 1994)
(ANSP 17795) premaxillary tooth (Fiorillo and Currie, 1994)
(ANSP 18005) maxillary tooth (Fiorillo and Currie, 1994)
(MOR 170) vertebra (MOR online)
(MOR 320) tooth (MOR online)
(MOR 993) (embryo) tooth, centrum, limb elements, partial egg (Varricchio and Jackson, 2004)
Late Campanian, Late Cretaceous
Oldman Formation of the Judith River Group, Alberta, Canada
(RTMP 89.77.5) tooth (Ryan and Russell, 2001)
(RTMP 94.157.1) eggshells (Zelenitsky, Modesto and Currie, 2002)
(RTMP 94.157.2) eggshells (Zelenitsky, Modesto and Currie, 2002)
(RTMP 94.157.4) eggshells (Zelenitsky, Modesto and Currie, 2002)
(RTMP 94.157.5) eggshells (Zelenitsky, Modesto and Currie, 2002)
(RTMP 138.319) tooth (Ryan, 2003)
(RTMP coll.) tooth (Chiba, Ryan, Braman, Eberth, Scott, Brown, Kobayashi and Evans, 2015)
teeth (Ryan and Russell, 2001)
(embryos and adults) material (Zelenitsky, Modesto and Currie, 2002)
Late Campanian, Late Cretaceous
Dinosaur Park Formation of the Judith River Group, Alberta, Canada
(AMNH 6174; Latenivenatrix morph) frontals (61.5 mm), parietals, laterosphenoid (Russell, 1969)
(AMNH 21598) tooth (AMNH online)
(AMNH 21714) tooth (AMNH online)
(CMN 199) distal tibia (58.6 mm wide), astragalus (Russell, 1969)
(CMN 1267) premaxillary tooth (Lambe, 1902)
(CMN 1650) distal manual phalanx, pedal ungual I (52 mm), phalanx II-1 (47.6 mm), phalanx II-2 (24.8, 24.6 mm), pedal ungual II (~70 mm), pedal ungual IV (~45 mm) (Russell, 1969)
(CMN 2506) pedal phalanx II-1 (Russell, 1969)
(CMN 8539; holotype of Stenonychosaurus inequalis) six distal caudal vertebrae, metacarpal I (36.5 mm), distal phalanx I-1, distal metacarpal II, partial phalanx II-1, distal manual phalanx, distal tibia, astragalus, metatarsal I, phalanx I-1 (~29 mm), pedal ungual I (~45 mm), metatarsal II (202.4 mm), phalanx II-1 (~50.5 mm), phalanx II-2 (29 mm), pedal ungual II, metatarsal III (253.6 mm), phalanx III-1 (~66 mm), phalanx III-2 (41.2 mm), phalanx III-3 (39.3 mm), pedal ungual III (~55 mm), metatarsal IV (244.5 mm), phalanx IV-1 (~34.2 mm), phalanx IV-2 (~28.3 mm), phalanx IV-3 (~23.6 mm), phalanx IV-4 (~24.5 mm), pedal ungual IV (~47 mm) (Sternberg, 1932)
(CMN 8540; holotype of Polyodontosaurus grandis; Latenivenatrix morph) dentary (117.5 mm) (Gilmore, 1932)
(CMN 12340; holotype of Latenivenatrix mcmasterae) postorbital, frontals (60.8 mm), parietals, basioccipital, basisphenoid, dorsal centrum fragment, four dorsal ribs, seven gastralia, three distal caudal vertebra fragments, three chevrons, proximal radius, ulnae (one distal) (131 mm), semilunate carpal, incomplete phalanx II-1, manual ungual, incomplete femur, astragali, metatarsal I, phalanx I-1 (26.3 mm), pedal ungual I (46.5 mm), metatarsal II fragments, phalanx II-1 (46.7 mm), pedal ungual II (65, 66 mm), metatarsal III fragments, phalanx III-1, phalanx III-3 (32.8 mm), pedal ungual III, metatarsal IV fragments, phalanx IV-1 (33.5 mm), phalanx IV-2 (27.3 mm), pedal ungual IV (~43 mm) (Russell, 1969)
(CMN 12355) frontal (Sues, 1978)
(CMN 12392) anterior maxilla, fragments (Russell, 1969)
(CMN 12425) astragalus (58.4 mm wide) (Russell, 1969)
(CMN 12433) ulna (138 mm) (Russell, 1969)
(CMN 12434) pedal phalanx II-1 (Russell, 1969)
(CMN coll.) distal metacarpal I (?), astragalus, calcaneum(?), distal metatarsal I (?), pedal ungual II (Lambe, 1902)
(ROM 1445) partial dentary, second dentary tooth, thirteenth dentary tooth, twentieth dentary tooth (Russell, 1948)
(RTMP 65.23.32) maxillary tooth (10 mm) (Currie, Rigby and Sloan, 1990)
(RTMP 67.14.39; = PMAA P67.14.39; Latenivenatrix morph) partial dentary (Sues, 1977)
(RTMP 79.8.1; Latenivenatrix morph) frontals (58.4 mm), parietals, laterosphenoid (Currie, 1985)
(RTMP 79.8.635) (juvenile) posterior dentary tooth (4 mm) (Currie, 1987a)
(RTMP 79.8.1171) tooth (Baszio, 1997)
(RTMP 80.16.1473) parietals (Currie, 1985)
(RTMP 80.16.1478; mistyped RTMP 80.16.1748 in van der Reest and Currie, 2017; Latenivenatrix morph) incomplete frontals (~140 mm), mesethmoid (Currie, 1985)
(TMP 1981.016.0231) incomplete frontal (Currie, 1992)
(RTMP 81.22.66) (Currie, 1985)
(RTMP 81.37.15) tenth cervical vertebra (Makovicky, 1995)
(RTMP 82.16.124) frontals, parietals (Currie, 1985)
(RTMP 82.16.138) partial dentary (Currie, 1987a)
(RTMP 82.16.282) premaxillary tooth (Currie, 1987a)
(RTMP 82.19.23; Latenivenatrix morph) lacrimal, postorbitals, squamosals, frontals, parietals, braincase (Currie, 1985)
(RTMP 82.19.151; mistyped RTMP 86.19.151 in van der Reest and Currie, 2017; Stenonychosaurus strat) partial dentary (Currie, 1987a)
(RTMP 82.20.259) premaxillary tooth (Currie, 1987a)
(RTMP 83.12.11; Latenivenatrix morph) incomplete dentary (Currie, Rigby and Sloan, 1990)
(RTMP 83.36.214) maxillary tooth (Currie, Rigby and Sloan, 1990)
(RTMP 83.36.215) tooth (Currie, Rigby and Sloan, 1990)
(RTMP 83.45.7) maxillary tooth (Currie, Rigby and Sloan, 1990)
(RTMP 83.45.8) tooth (Currie, Rigby and Sloan, 1990)
(RTMP 84.65.1) distal metatarsal II, incomplete metatarsal III, distal metatarsal IV (Wilson and Currie, 1985)
(RTMP 85.6.3) premaxillary tooth (Currie, Rigby and Sloan, 1990)
(RTMP 85.6.186) maxillary tooth (Currie, Rigby and Sloan, 1990)
(RTMP 86.36.4; Latenivenatrix morph?) frontals, parietals (Currie, 1987b)
(RTMP 86.36.457; Stenonychosaurus strat) incomplete braincase (Currie and Zhao, 1993)
(RTMP 86.49.10; Stenonychosaurus morph) frontal (62.4 mm) (Currie, 1987b)
(RTMP 86.54.66) premaxillary tooth (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 86.78.40; Stenonychosaurus morph) frontal (Evans et al., 2017)
(RTMP 86.177.8) maxillary tooth (Sankey, Brinkman, Guenther and Currie, 2002)
(RTMP 88.50.58) tooth (Baszio, 1997)
(RTMP 88.50.88; Stenonychosaurus morph) partial frontals, partial parietals (van der Reest and Currie, 2017)
(RTMP 88.96.2) maxillary tooth (Currie, Rigby and Sloan, 1990)
(RTMP 89.36.268) tooth (Ryan and Russell, 2001)
(RTMP 89.76.50) tooth (Baszio, 1997)
(RTMP 89.77.5) tooth (Baszio, 1997)
(RTMP 89.89.4) tooth (Baszio, 1997)
(RTMP 89.116.63) tooth (Baszio, 1997)
(RTMP 90.34.1) tooth (Baszio, 1997)
(RTMP 91.36.690; Stenonychosaurus morph?) frontal (van der Reest and Currie, 2017)
(RTMP 92.36.575; Latenivenatrix morph) incomplete dentary (~160 mm), partial tibia, metatarsal II, distal metatarsal III (258.8 mm), metatarsal IV (266.2 mm), metatarsal V (74.1 mm) (Rauhut, 2003)
(RTMP 92.36.1212) (adult) posterior cervical vertebra (Makovicky, 1995)
(RTMP 93.36.86; Latenivenatrix morph) frontal (62.5 mm) (Evans et al., 2017)
(RTMP 94.12.438) third dorsal vertebra (Makovicky, 1995)
(RTMP 97.133.8; Latenivenatrix morph) metatarsal III (van der Reest and Currie, 2017)
(RTMP 98.68.90; Stenonychosaurus morph) metatarsal III (van der Reest and Currie, 2017)
(RTMP 98.93.1; Latenivenatrix morph) frontal (55.1 mm) (Evans et al., 2017)
(UALVP 5282; Stenonychosaurus morph) incomplete frontal (Russell, 1969)
(UALVP 5284) distal metatarsal III (Russell, 1969)
(UALVP 52611; Stenonychosaurus morph) frontals (60.5 mm), parietals (Evans et al., 2017)
(UALVP 55285; Latenivenatrix morph?) frontal (van der Reest and Currie, 2017)
(UALVP 55804; Latenivenatrix strat) sacrum (207.4 mm), ilia (one partial; ~308 mm), partial pubes (van der Reest and Currie, 2017)
(YPM PU 23414; Latenivenatrix morph) parietals (Currie, 1985)
teeth (Brinkman, 1990)
Campanian, Late Cretaceous
Two Medicine Formation, Montana, US
(MOR 246) nest (Horner and Weishampel, 1988)
....(MOR 246-1) (embryo) teeth, two cervical centra (4.4 mm), cervical neural arch, sacral centrum (5.1 mm), scapula (14.7 mm), fragmentary coracoid, humerus (20.3 mm), partial tibiae, partial fibula, egg
....(MOR 246-2) (embryo) humerus, egg
....(MOR 246-3) egg
....(MOR 246-5) (embryo) bone, egg
....(MOR 246-7) (embryo) bone, egg
....(MOR 246-8) (embryo) femur, egg
....(MOR 246-9) (embryo) bone, egg
....(MOR 246-10) (embryo) bone, egg
....(MOR 246-11) (embryo) (skull ~50 mm) maxilla (~18 mm), quadrate (12.1 mm), basioccipital, teeth (1 mm), vertebrae, ilia, pubes (~23 mm), ischial fragments, femur (34.9 mm), tibiae (46 mm), partial fibula, metatarsal II, metatarsal III, metatarsal IV (33.5 mm)
....(MOR 246-12) egg
....(MOR 246-13) (embryo) bone, egg
....(MOR 246-14) egg
....(MOR 246-15) egg
....(MOR 246-16) (embryo) bone, egg
....(MOR 246-17) (embryo) bone, egg
....(MOR 246-18 (embryo) bone, egg
(MOR 247) egg (Varricchio, Horner and Jackson, 2002)
(MOR 299) eggs (Varricchio, Horner and Jackson, 2002)
(MOR 323) tooth (MOR online)
(MOR 363-7-4-83-1) nest, twenty-two eggs (Varricchio, Jackson, Borkowski and Horner, 1997)
(MOR 393) nest, twenty-two eggs (Varricchio, Horner and Jackson, 2002)
(MOR 430) (several month old juvenile) partial skeleton including premaxilla, caudal vertebrae, femur (126 mm), tibia (173 mm), metatarsal IV (105 mm) (Currie, Rigby and Sloan, 1990)
(MOR 493) metatarsals, pedal phalanges (MOR online)
(MOR 510) tooth (MOR online)
(MOR 511) teeth (MOR online)
(MOR 512) teeth (MOR online)
(MOR 513) teeth (MOR online)
(MOR 553) anterior dorsal vertebra, distal caudal vertebrae (Makovicky, 1995)
(MOR 553-1) metatarsal II, metatarsal III, metatarsal IV (Varricchio, 1993)
(MOR 553-2) metatarsal (Varricchio, 1997)
(MOR 553-6.21.9) fourth cervical vertebra (Makovicky, 1995)
(MOR 553-7.7.91.19) tibia (Zanno et al., 2011)
(MOR 553-7.16.0.61) femur (Varricchio, 1993)
(MOR 553-7.21.92.46) (adult) ninth or tenth cervical vertebra (Makovicky, 1995)
(MOR 553-7.24.8.64) tibia (425 mm) (Varricchio, 1993)
(MOR 553-7.28.91.236) tenth cervical vertebra (Makovicky, 1995)
(MOR 553-7.20.91.120) anterior dorsal vertebra (Makovicky, 1995)
(MOR 553-7.23.91.36) first caudal vertebra (Makovicky, 1995)
(MOR 553-8.3.92.141) (adult) eighth cervical vertebra (Makovicky, 1995)
(MOR 553-8.8.92.186) first dorsal vertebra (Makovicky, 1995)
(MOR 553-8.10.92.203) (adult) twelfth dorsal vertebra (Makovicky, 1995)
(MOR 553-8.11.92.204) third cervical vertebra (Makovicky, 1995)
(MOR 553-8.12.92.222) (juvenile) eighth or ninth cervical vertebra (Makovicky, 1995)
(MOR 553-8.19.92.212) fourth cervical vertebra (Makovicky, 1995)
(MOR 553-8.20.92.305) (adult) sixth or seventh dorsal vertebra (Makovicky, 1995)
(MOR 553D) partial sacrum (Makovicky, 1995)
(MOR 553L-7.25.89.313) pedal ungual II (Wolff, Varricchio and Hanna, 2015)
(MOR 553L-7.27.8.87) ischium (Hutchinson, 2001)
(MOR 553S) material including more precise specimens below and the following which may be those specimens- four humeri (129.4, 143.4, 146.7, 178.7 mm), pubis, ischium, five femora (218.0, 233.0, 238.0, 273.0, 302.0 mm), six tibiae (283.0, 317.0, 323.0, 361.0, 382.0, 431.0 mm) and three metatarsals III (114.3, 124.2, 130.7 mm) (Carrano, 1998)
(MOR 553S-7.1.9.9) metatarsal IV (Zanno et al., 2011)
(MOR 553S-7.8.91.28) metatarsal II (Zanno et al., 2011)
(MOR 553S-7.16.0.61) (adult) femur (Zanno et al., 2011)
(MOR 553S-7.18.92.5) metatarsal II (Zanno et al., 2011)
(MOR 553S-7.20.91.120) dorsal vertebra (Wolff, Varricchio and Hanna, 2015)
(MOR 553S-7.21.92.47) maxilla (MOR online)
(MOR 553S-7.28.8.102) metatarsal IV (Zanno et al., 2011)
(MOR 553S-7.28.91.236) cervical vertebra (Wolff, Varricchio and Hanna, 2015)
(MOR 553S-7.28.91.239) (adult) femur (Zanno et al., 2011)
(MOR 553S-7.29.92.113) metatarsal III (Zanno et al., 2011)
(MOR 553S-8.2.91.303) humerus (MOR online)
(MOR 553S-8.2.92.131) braincase (MOR online)
(MOR 553S-8.3.9.387) pubis (Zanno et al., 2011)
(MOR 553S-8.3.92.141) cervical vertebra (Wolff, Varricchio and Hanna, 2015)
(MOR 553S-8.12.92.219) ulna (Zanno et al., 2011)
(MOR 553S-8.13.92.237) metacarpal II (Wolff, Varricchio and Hanna, 2015)
(MOR 553S-8.17.92.260) metatarsal IV (Wolff, Varricchio and Hanna, 2015)
(MOR 553S-8.17.92.265) fibula (Zanno et al., 2011)
(MOR 553S-8.20.92.305) mid dorsal vertebra (Zanno et al., 2011)
(MOR 553S-8.20.92.311) astragalus (Zanno et al., 2011)
(MOR 553S-8.28.92.270) mid dorsal vertebra (Zanno et al., 2011)
(MOR 553S-8.69.406) metatarsal III (Zanno et al., 2011)
(MOR 553S-11.1.01.1) astragalus (Zanno et al., 2011)
(MOR 553S-11.1.01.8; = MOR 553S 1.11.01.8 of Wolff, Varricchio and Hanna, 2015?) metatarsal IV (Zanno et al., 2011)
(MOR 553S-92.260) metatarsal IV (Zanno et al., 2011)
(MOR 558) braincase, three cervical vertebrae, elements (MOR online)
(MOR 563) (year old juvenile) skeleton including tibia, metatarsal III (Varricchio, 1993)
?(MOR 564) (embryo) maxilla (MOR online)
?(MOR 584) partial skeleton (MOR online)
(MOR 615) eggs (MOR online)
(MOR 646) jaw fragment (MOR online)
(MOR 675) eggs (Varricchio, Horner and Jackson, 2002)
(MOR 676) two nests including eleven and eight eggs (Varricchio, Horner and Jackson, 2002)
(MOR 702) two eggs (Varricchio and Jackson, 2004)
(MOR 721) specimen including femur (156.9 mm) and tibia (224 mm) (Carrano, 1998)
(MOR 748) (12 year old adult) nine proximal caudal vertebrae, eight distal caudal vertebrae, partial pelvis, femur (320 mm), tibia (362 mm), fibula, astragalus, metatarsal I, metatarsal II, metatarsal III (206.5 mm), metatarsal IV (227 mm), four pedal phalanges, nest, at least ten eggs (Varricchio, Jackson, Borkowski and Horner, 1997)
(MOR 750) eggs (Varricchio, Horner and Jackson, 2002)
(MOR 796) five vertebrae, partial ribs (MOR online)
(MOR 963) nest, twenty-four eggs (Varricchio, Jackson, Borkowski and Horner, 1997)
(MOR 964) eggs (MOR online)
(MOR 1006) partial egg (MOR online)
(MOR 1115) twenty-four eggs (MOR online)
(MOR 1138) eggs (MOR online)
(MOR 1139) eggs (Varricchio, Horner and Jackson, 2002)
(MOR 1170) tibia (MOR online)
(MOR coll.) caudal series (Wolff, Varricchio and Hanna, 2015)
(YPM PU 22445) (YPM online)
(YPM PU 23246-23248) (YPM online)
(YPM PU 22544) (Hirsch and Quinn, 1990)
(YPM PU 22594) (Hirsch and Quinn, 1990)
(YPM PU 23259) (YPM online)
(YPM PU 23408) (YPM online)
(YPM PU 23409) (YPM online)
teeth (Redman, Moore and Varricchio, 2015)
Diagnosis- (after Currie, 1987a; compared to Saurornithoides and Zanabazar) round anterior border of antiorbital fenestra; sculpturing less extensive on nasal process of maxilla; postorbital region of skull longer; no sulcus between parasphenoid capsule and rectangular platform between basipterygoid processes; mesethmoid located further anteriorly; very strong, caudoventrally shifted basal tubera; otic recess extends further posteroventrally; dentary symphysis more extensive; mesial serrations extend to tip of carina on maxillary teeth.
(after van der Reest and Currie, 2017; for Latenivenatrix, but unknown in Stenonychosaurus) 17° retroverted pubis; anteriorly curving pubic shaft; large muscle scar on lateral surface of pubic shaft slightly proximal to pubic boot.
Other diagnoses- Leidy's (1856) original description of Troodon included both generalized theropod characters ("compressed, curved, conical crown with trenchant edges ... outer side is more convex than the inner") and those now known to be present in other troodontines ("trenchant edges are coarsely denticulated; the denticulations themselves being compressed conical, with trenchant edges, and are bent in such a manner that their apices are directed towards the summit of the crown").
Ornithischian or theropod?- Troodon was originally discovered in October 1855 and identified as a lizard by Leidy (1856) based on the holotype tooth, but reidentified as a theropod by Cope (1877). Nopcsa (1901) and Hay (1902) placed it in Megalosauridae. Brown (1908) placed it in Ankylosauridae, while Gilmore (1924) believed it was a pachycephalosaurid and a senior synonym of Stegoceras. Thus pachycephalosaurs were classified under Gilmore's new family Troodontidae until Sternberg (1945) placed Troodon back in Theropoda and named Pachycephalosauridae. Russell (1948) described a partial dentary (ROM 1445) of Troodon, assigning it to Troodontidae within the Theropoda. A further confusion with ornithischians occured when Galton (1983) suggested "Laosaurus" minimus should be assigned to Troodon and that the latter is a carnivorous ornithopod (first suggested by Baird, 1981). Galton cited pers. comm. with Horner alluding to undescribed Two Medicine Formation material. The latter turned out to be adults of the ornithopod Orodromeus (Horner and Weishampel, 1988) associated with Troodon teeth, eggs and embryos (Horner and Weishampel, 1996). The idea of Troodon as a carnivorous ornithopod was never established in the technical literature, but was widespread in the popular literature in the 1980's. Instead, it was almost always assigned to Theropoda after 1945.
Laelaps cristatus- Cope (1876) described two teeth as a new species of Laelaps (in which he placed all Judithian theropods). Once Marsh provided the replacement name Dryptosaurus for the preoccupied Laelaps, Hay (1902) moved cristatus to that genus. Osborn (1902) meanwhile referred it to Deinodon, though this is not the same taxon as Hay's (1902) Deinodon cristatus, which was a new combination of Aublysodon cristatus, a tyrannosaurid premaxillary tooth. Matthew and Brown (1922) questionably referred the species to their new genus Dromaeosaurus, probably based on size, for it was the smallest of their 'deinodontids'. Olshevsky (1995) most recently referred it to Troodon, though most workers have ignored it. This tooth can indeed be identified as Troodon by its large serrations (2/mm distally, and slightly smaller mesially), presence of mesial serrations and absence of longitudinal ridges. The size (FABL 6 mm) and BW/FABL (.50) are also comparable to Troodon maxillary teeth (Currie et al., 1990), as is the height/FABL (1.83). The serrations are smaller than in premaxillary teeth, which is why Cope kept it separate from Troodon (at the time only known from the type premaxillary tooth). The tooth is larger than dentary teeth, posterior examples of which also differ in lacking mesial serrations. As it is from the same formation as T. formosus and lacks distinguishing characters, it is referred to that species here.
Polyodontosaurus grandis- Sternberg collected a dentary (CMN 8540) from the same formation as Leidy's specimen, which Gilmore (1932) described as a new genus of lizard- Polyodontosaurus. Sternberg later (1951) assigned this genus to Troodontidae, noting it may be congeneric with Troodon. The latter synonymization was formalized by Romer in 1966, who assigned both to the Coeluridae. On the other hand, Russell (1969) synonymized Polyodontosaurus with Stenonychosaurus inequalis in the Troodontidae.
Stenonychosaurus and Saurornithoides- Sternberg (1932) named Stenonychosaurus inequalis as a coelurid, based on a fragmentary skeleton (CMN 8539). Sternberg later (1951) suggested Stenonychosaurus and Troodon might be synonymous, but no comparable elements were known which could prove this. Russell (1969) described several specimens found in 1968 as Stenonychosaurus inequalis, assigning it to the Troodontidae along with Saurornithoides and Troodon. He did not synonymize Troodon with Stenonychosaurus or Saurornithoides due to the fragmentary condition of the former. Ostrom (1969) assigned both Saurornithoides and Stenonychosaurus to the Dromaeosauridae based on their raptorial second pedal digit, though perhaps deserving subfamilial status. Barsbold (1974) noted differences between the holotype of Troodon and teeth of Saurornithoides, while feeling the cranial and postcranial resemblences between Stenonychosaurus and Saurornithoides justified a close relationship. He assigned the latter two genera to his new family Saurornithoididae, while retaining Troodon in Troodontidae. This was followed until Currie (1987a). Sues (1977) described two new dentaries as saurornithoidids, though he was uncertain if they belonged to Stenonychosaurus or Saurornitholestes (which was assigned to Dromaeosauridae once he described it the next year). Stenonychosaurus was generally used for the Dinosaur Park troodontid through the 1980's (e.g. Currie, 1985), though Carpenter (1982) synonymized it with Saurornithoides, as Saurornithoides inequalis. This was done without justification however, referencing a Carpenter and Paul in prep. publication which never emerged. Paul did later (1988) synonymize Saurornithoides with Troodon (including Stenonychosaurus), but this is a subjective decision which has not been accepted by later authors.
Estes (1964) originally referred several teeth from the Lance Formation of Wyoming to Saurornithoides sp.. Carpenter (1982) named Pectinodon bakkeri from the same formation, believing some of Estes' specimens to be referrable to that species, some to his new combination Saurornithoides inequalis, and others to an unnamed third taxon. He assigned Pectinodon to the Saurornithoididae.
Currie's breakthrough- Currie (1987a) cleared up the American troodontid situation, determining the differences between known dentaries were ontogenetic, and dental differences between Troodon, ROM 1445, Saurornithoides and the Lance Formation specimens were largely due to variation within the tooth row. Troodon's holotype is a premaxillary tooth, the teeth of Saurornithoides which Barsbold compared were maxillary (as were Carpenter's Saurornithoides inequalis examples), Pectinodon was based on posterior dentary teeth, while ROM 1445 contains a few dentary teeth. Currie described intermediates between all of these morphologies, although he noted the maxillary mesial serrations are more extensive in Troodon than Saurornithoides, extending to the tip of the tooth. He synonymized Stenonychosaurus inequalis and Polyodontosaurus grandis with Troodon formosus, and provisionally did the same for Pectinodon bakkeri. This has remained the consensus, along with the assignment of Saurornithoides, Troodon and related taxa to the Troodontidae.
Overlumped?- Recently the concept of all Campanian-Maastrichtian North American troodontids being one taxon has been questioned. Currie et al. (1990) noted that though Horseshoe Canyon Formation troodontid teeth are essentially identical to those from the Judith River Group/Formation, teeth from the Frenchman, Hell Creek, Lance, Prince Creek and Scollard Formations are different and may prove to be separate species. Baszio (1997) elaborated, describing differences between teeth from the Judith River, Horseshoe Canyon and Scollard Formations. Olshevsky (1991) created the new combination Troodon bakkeri for the Lance Formation material, while several papers have used the combination Troodon inequalis for the Dinosaur Park Formation taxon (Snively, 2002; Osmólska, 2004; Currie, 2005). Currie (2005) stated that it is more conservative to retain inequalis for Dinosaur Park specimens, but keeping taxa separate based on a political boundary (Montana vs. Alberta) has no biological value.
Morhardt et al. (2013) and Evans et al. (2017) both describe cranial differences between Dinosaur Park and Horseshoe Canyon specimens, Evans et al. naming frontals from the latter formation Albertavenator curriei. Sankey et al. (2002) have split Dinosaur Park Formation troodontids into Troodon formosus and cf. Troodontidae indet., with the latter being a rare form only present in some formations and distinguished by various dental characters. If they are correct, most of the non-dental specimens (including the Stenonychosaurus holotype and CMN 12340) could not be definitively assigned to either taxon, and many poorly or undescribed Troodon teeth could end up not being referrable to that genus. Conversely, Evans et al. (2017) analyzed teeth morphometrically and recovered the Troodon holotype very close to an apparent premaxillary tooth from the Horseshoe Canyon Formation, which may indicate premaxillary teeth of Albertavenator cannot be distinguished from Troodon and thus the latter is indeterminate. They note the frontals can be distinguished, and that CMN 12340 allows connecting frontal morphology with the supposedly diagnostic pedal anatomy of Stenonychosaurus inequalis. This could support a valid Stenonychosaurus and Albertavenator. However, there is only stratigraphic evidence to connect any teeth with Albertavenator, so it's also possible e.g. that particular Hoseshoe Canyon tooth is Troodon, and that the three widely separated premaxillary teeth in the lower left of their figure 6j are Albertavenator.
Most recently, van der Reest and Currie (2017) have used frontal and metatarsal III differences correlated with stratigraphy to divide Dinosaur Park troodontids into smaller, earlier Stenonychosaurus inequalis (diagnosis- L-shaped frontal with a flat shallowly anteroposteriorly rippled nasofrontal contact; convex anterior surface of metatarsal III) and larger, later Latenivenatrix mcmasterae (diagnosis- triangular frontal with a single deep groove in the frontonasal contact surface; concave anterior surface of metatarsal III) with CMN 12340 as the holotype. Further noted differences are anteriorly expanded parietal sagittal crest and anteriorly limited medial recurvature of dentary in Stenonychosaurus. In addition to their specimen identifications, RTMP 86.49.10 has a Stenonychosaurus morphology (Currie, 1987b), while RTMP 67.14.39 (Sues, 1977), RTMP 83.12.11 (Evans et al., 2017), RTMP 93.36.86 (Evans et al., 2017) and YPM PU 23414 (Currie, 1985) have a Latenivenatrix morphology. Notably, this does not allow any teeth including the Troodon holotype to be referred to either taxon, nor any described material from the Judith River Formation of Montana where T. formosus' holotype is from. Also, the holotype dentary of Polyodontosaurus grandis was reported to be placed stratigraphically high in the Latenivenatrix range (Gilmore, 1932) although van der Reest and Currie bring up potential sources for error. Its extensive and strong medial curvature also matches Latenivenatrix more than Stenonychosaurus, but this is also present in e.g. ?Albertavenator and Zanabazar so is not an autapomorphy, and the Stenonychosaurus dentary is only referred to that taxon based on stratigraphy. So there is evidence Polyodontosaurus is a senior synonym of Latenivenatrix, but this is uncertain. A final factor is the identity of the Two Medicine Formation troodontid, which has yet to be described in detail. van der Reest and Currie (2017) report that it and Talos share the anteriorly convex distal metatarsal III with Stenonychosaurus, unlike Latenivenatrix, Linhevenator and Gobivenator. The skull roof and dentary are not yet described. If this taxon is described as Stenonychosaurus or a new taxon, it's likely Troodon will be broken down on this site into several genera with the incomparable Dinosaur Park specimens and current T? sp. being made into unnamed/undescribed/indet. Troodontinae.
Troodon eggs and embryos- Horner (1982) first reported ten nests in the Two Medicine Formation which he ascribed to ornithopods, "closely allied to the Hypsilophodontidae". Horner and Weishampel later (1988) described a new genus of ornithopod from the site, Orodromeus makelai. They believed abundant nest with eggs and embryos belonged to Orodromeus, though this was disproven by Horner and Weishampel (1996) due to the small size of adult Orodromeus and the reidentification of an embryo as Troodon. Zelenitsky and Hillis (1996) named eggs from the Oldman Formation of Alberta Prismatoolithus levis (Prismatoolithidae), while Zelenitsky (2000) identified the Two Medicine Formation Troodon eggs as belonging to this oospecies as well. Most of the publications dealing with Troodon since that time have concerned these nests, eggs and embryos.
One confusing aspect is that Continuoolithus canadensis eggs were provisionally assigned to Troodon by Horner (1984), based on an embryo. This was followed by Hirsch and Quinn (1990) and Horner (1994), until 1996. Horner (1997) found the embryo to be indeterminate, while Varricchio and Jackson (2004) found the eggshell to be theropod. The precise identity of Continuoolithus is still unknown.
Canadian therizinosaur frontals?- Sues (1978) identified frontal CMN 12349 as Dromaeosaurus and frontal CMN 12355 as Theropoda indet., although note his plates 7 and 8 are switched so that they are given each others' captions. Currie (1987b) accepted CMN 12349 as Dromaeosaurus, but with regard to CMN 12355 stated that "comparison with Mongolian specimens suggests that it may represent Erlicosaurus (Currie, in preparation)." Currie (1992) again stated CMN 12355 "may represent the segnosaurid Erlicosaurus" (although note that as in Sues' paper it is mislabeled 12349 in his Figure 2) and also referred TMP 1981.016.0231 to Segnosauridae. Currie (2005) listed CMN 12349 as a tentative "therizinosauroid similar to Erlikosaurus", but figured CMN 12355 so probably meant that specimen. Indeed, it seems CMN 12349 was correctly identified as Dromaeosaurus in the first place as it is similar to the holotype and has only been referred to Therizinosauroidea accidentally due to Sues' original plate caption mistake. Larson et al. (2014) performed a morphometric analysis of Dinosaur Park coelurosaur frontals, and found that CMN 12355 grouped with Troodon, so is troodontid instead. Yet without including a therizinosaur such as Erlikosaurus itself, the study only had so much explanatory power. More recently, Cullen et al. (2020) expanded the analysis to include both Erlikosaurus and the Bissekty therizinosaurid, still recovering CMN 12355 within the Dinosaur Park troodontid range and far from therizinosaurids. Both it and the less complete TMP 1981.016.0231 are here referred to Troodon formosus sensu lato.
Reinterpreted records- The supposed Struthiomimus manual ungual in plate XV figure 10-11 of Lambe (1902) is not ornithomimid and may be a Troodon pedal ungual II instead. Found with this and apparently similar unguals and manual phalanges were an astragalus, calcaneum, pedal phalanges and two elements identified by Lambe as distal ends of metacarpal I and metatarsal I. A metatarsal I would exclude ornithomimids from consideration, but a calcaneum would exclude troodontids. It's probable some material was incorrectly associated or misidentified. Though Britt (1993) described the posterior cervical vertebrae RTMP 81.37.15 and 92.36.1212 as ornithomimids, Makovicky (1995) indicated they were actually Troodon.
Although Currie et al. (1990) reported Troodon from the Milk River Formation, Baszio (1997) notes the ROM specimens noted were collected in the Milk Creek area, but probably in the Judith River Group. A large sample of theropod teeth from the Milk River Formation did not include Troodon.
Rowe et al. (1992) and Sankey (1997, 1998) identified Troodon in the Aguja Formation of Texas based on teeth (TMM 43057-323 and LSUMG 140:6117 respectively), but these were later identified as pachycephalosaurian by Sankey (2001). This would mean Troodon is unknown from the Aguja Formation, except that Montellano et al. (2009) later reported cf. Troodon teeth in an abstract. Whether these are truly troodontid awaits proper description.
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T? bakkeri (Carpenter, 1982) Olshevsky, 1991
= Pectinodon bakkeri Carpenter, 1982
Late Maastrichtian, Late Cretaceous
Lance Formation, Wyoming, US
Holotype- (UCM 38445; holotype of Pectinodon bakkeri) tooth (6.2x3.7x? mm)
Paratypes- (UCM 38446) (juvenile) tooth (1.8x2x? mm)
(UCMP 73098) (juvenile) tooth (2.8x1.8x? mm)
(UCMP 125239; was part of UCMP 73098) (juvenile) tooth (3.2x2.5x? mm)
Referred- (SDSM 12456) four dentary teeth (Whitmore, 1988)
(SDSM 12458) maxillary tooth (Whitmore, 1988)
(SDSM 15098) three dentary teeth (Whitmore, 1988)
(SDSM 15099) maxillary tooth (Whitmore, 1988)
(UA 156) tooth (Baszio, 1997)
(UA 157) tooth (Baszio, 1997)
(UCM 41666) (juvenile) anterior dentary (Carpenter, 1982)
(UCM 43218) (juvenile) basioccipital (Carpenter, 1982)
(UCMP 84990) tooth (UCMP online)
(UCMP 125240; = UCMP 124402) tooth (Carpenter, 1982)
(UCMP 125241; = UCMP 124394) tooth (Carpenter, 1982)
(UCMP 125242; = UCMP 124394) tooth (Carpenter, 1982)
(UCMP 125243; = UCMP 124394) tooth (Carpenter, 1982)
(UCMP 125244; = UCMP 124394) tooth (Carpenter, 1982)
(UCMP 125245; = UCMP 124394) tooth (Carpenter, 1982)
(UCMP 125246; = UCMP 124394) tooth (Carpenter, 1982)
(UCMP 125247; = UCMP 124394) tooth (Carpenter, 1982)
(UCMP 186864) teeth (UCMP online)
(UCMP 186886) teeth (UCMP online)
(UCMP 186916) tooth (UCMP online)
(UCMP 186979) tooth (UCMP online)
(UCMP 187050-187056) seven teeth (UCMP online)
(UCMP 187058-187079) twenty-two teeth (UCMP online)
(UCMP 187180) tooth (UCMP online)
(UCMP 187181) tooth (UCMP online)
?(UCMP 189686) ungual (UCMP online)
(UCMP 214059) tooth (UCMP online)
(YPM 54491) (YPM online)
(YPM 55041) (YPM online)
(YPM 55521) (YPM online)
(YPM 55536) (YPM online)
(YPM 55545) (YPM online)
(YPM 55546) (YPM online)
(YPM 55583) (YPM online)
(YPM 55584) (YPM online)
(YPM 55591) (YPM online)
(YPM 55592) (YPM online)
(YPM 55627) (YPM online)
teeth (Derstler, 1995)
(juvenile) elements, eggshells (Derstler, 1995)
teeth (Spencer, Turner and Chadwick, 2001)
Late Maastrichtian, Late Cretaceous
Lance Formation, Montana, US
(CM 30748) partial humerus, ulna, femora, tibia (McIntosh, 1981)
Late Maastrichtian, Late Cretaceous
Hell Creek Formation, Montana, US
(UCMP 364730; = UCMP 556335) tooth (UCMP online)
Late Maastrichtian, Late Cretaceous
Hell Creek Formation, South Dakota, US
teeth (DePalma, 2010)
Other diagnoses- (after Carpenter, 1982) crowns of teeth strongly compressed labiolingually and recurved; mesial margin without serrations or sharp, translucent carina; mesial edge usually rounded, but may have low, blunt, opaque carina; distal margin with large serrations having translucent edges; serrations largest in middle, and may be subequal to crown's tip in size; distal serrations perpendicular to vertical axis of tooth; crown tip directed distally, almost parallel to crown base; crown tip does not function as a piercing tip, but as first serration; first definitive serration occurs immediately below crown tip and differs from other deinonychosaurs in that it is not significantly smaller than crown tip; near tooth's base, two small serrations are crowded together; FABL of tooth almost equal to height.
Comments- Estes (1964) referred teeth to Saurornithoides sp., but these seem to belong to a different species of troodontid (cf. Troodontidae indet. of Sankey et al., 2002). Carpenter (1982) described several teeth as Pectinodon bakkeri, believing them to be distinct from Judith River troodontids, though Currie showed this was due to their position in the jaw (posterior dentary). Virtually no Lance Formation troodontid material has been described except this material, which Currie (1987) felt was indistinguishable from Judith River Troodon, though Currie et al. (1990) stated they were somewhat different. Derstler (1995) considered his juvenile material and eggshells to belong to a new taxon of troodontid. Olshevsky (1991) created the new combination Troodon bakkeri for Lance Formation troodontid teeth, which is used here because the basal tubera are large and the dentary symphysis seems more robust than Zanabazar, though not as much as in T. formosus (due to ontogeny?). All Lance Formation troodontid material is listed here.
References- Estes, 1964. Fossil vertebrates from the Late Cretaceous Lance Formation, eastern Wyoming. University of California Publications in Geological Sciences. 49, 1-180.
McIntosh, 1981. Annotated catalogue of the dinosaurs (Reptilia, Archosauria) in the Collections of Carnegie Museum of Natural History. Bulletin of the Carnegie Museum of Natural History. 18, 1-67.
Carpenter, 1982. Baby dinosaurs from the Late Cretaceous Lance and Hell Creek formations and a description of a new species of theropod. Contributions to Geology, University of Wyoming. 20(2), 123-134.
Currie, 1987. Bird-like characteristics of the jaws and teeth of troodontid theropods (Dinosauria, Saurischia). Journal of Vertebrate Paleontology. 7, 72-81.
Whitmore, 1988. The vertebrate paleontology of Late Cretaceous (Lancian) localities in the Lance Formation, Northern Niobrara County, Wyoming. Masters Thesis. South Dakota School of Mines and Technology. 130 pp.
Currie, Rigby and Sloan, 1990. Theropod teeth from the Judith River Formation of southern Alberta, Canada. in Carpenter and Currie (eds.). Dinosaur Systematics: Perspectives and Approaches. Cambridge University Press, New York. pp. 107-125.
Olshevsky, 1991. A Revison of the Parainfraclass Archosauria Cope, 1869, Excluding the Advanced Crocodyila. Mesozoic Menanderings #2 (1st printing). iv + 196pp.
Derstler, 1995. The Dragons’ Grave - an Edmontosaurus bonebed containing theropod egg shells and juveniles, Lance Formation, (Uppermost Cretaceous), Niobrara County, Wyoming. Journal of Vertebrate Paleontology. 15(3), 26A.
Baszio, 1997. Investigations on Canadian dinosaurs: Systematic palaeontology of isolated dinosaur teeth from the Latest Cretaceous of south Alberta, Canada. Courier Forschungsinstitut Senckenberg. 196, 33-77.
Spencer, Turner and Chadwick, 2001. A remarkable vertebrate assemblage from the Lance Formation, Niobrara County, Wyoming. GSA Annual Meeting and Exposition Abstracts. 33(6), A-197.
Sankey, Brinkman, Guenther and Currie, 2002. Small theropod and bird teeth from the Late Cretaceous (Late Campanian) Judith River Group, Alberta. Journal of Paleontology. 76(4), 751-763.
DePalma, 2010. Geology, taphonomy, and paleoecology of a unique Upper Cretaceous bonebed near the Cretaceous-Tertiary boundary in South Dakota. Masters thesis, University of Kansas. 227 pp.
T? sp. (Currie, Rigby and Sloan, 1990)
Campanian, Late Cretaceous
Prince Creek Formation, Alaska, US
Material- (AK83-V-095) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK138-V-128) (subadult) partial braincase (Fiorillo et al., 2009)
(AK233-V-054) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK282-V-001) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK282-V-010) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK282-V-052) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK282-V-056) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK283-V-017) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK283-V-115) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK284-V-024) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK285-V-008) premaxillary tooth (Fiorillo and Gangloff, 2000)
(AK285-V-013) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK285-V-037a) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK299-V-134) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK300-V-017) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK300-V-021) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK300-V-042) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK300-V-055) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK300-V-060) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK300-V-129) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK335-V-012FT) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK335-V-076) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK382-V-015) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK382-V-105) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK383-V-018) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK383-V-137) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK383-V-140) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK383-V-176) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK383-V-183) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK385-V-001) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK385-V-002) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK387-V-000FT) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK387-V-017) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK388-V-002) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK388-V-082) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK392-V-007) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK459-V-011) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK498-V-001) tooth (Fiorillo, 2008)
(AK490-V-004) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK490-V-008FL) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK490-V-086FT) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK491-V-143) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK491-V-168) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK497-V-002) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK498-V-001) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK498-V-002) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK498-V-003) maxillary or dentary tooth (Fiorillo and Gangloff, 2000)
(AK coll.) thirty-three teeth (Fiorillo, 2008)
(DMNH 22158) (adult) partial braincase (Fiorillo et al., 2009)
(UCMP 140624; lost) three teeth (UCMP online)
skull fragments (Gangloff, 1998)
Comments- The two braincases were described as T. formosus, apparently identical to that species except for some pneumatic features, which are known to exhibit marked individual and symmetry variation. These teeth have not been described in detail, though Currie et al. (1990) noted they were somewhat different than Judith River Troodon teeth, and Sankey et al. (2002) said that no examples of their cf. Troodontidae indet. were present in this formation. Fiorillo (2008) found the teeth to be larger on average than T. formosus (9.78 mm in length vs. 4.96 mm), but indentical in length vs. FABL. The Alaskan teeth range from 5.4-14.3 mm in length and 4.3-9 mm in FABL.
References- Currie, Rigby and Sloan, 1990. Theropod teeth from the Judith River Formation of southern Alberta, Canada. in Carpenter and Currie (eds.). Dinosaur Systematics: Perspectives and Approaches. Cambridge University Press, New York. pp. 107-125.
Nelms, 1992. Paleoecological implications of a North Slope Dinosaurian assemblage. International Conference on Arctic Margins, Abstracts. 42.
Gangloff, 1998. Arctic Dinosaurs with Emphasis on the Cretaceous Record of Alaska and the Eurasian-North American Connection. Kirkland, Lucas and Estep (eds). Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science, Bulletin. 14, 211-220.
Fiorillo and Gangloff, 2000. Theropod teeth from the Prince Creek Formation (Cretaceous) of Northern Alaska, with speculations on Arctic dinosaur paleoecology. Journal of Vertebrate Paleontology. 20(3), 41A.
Fiorillo and Gangloff, 2000. Theropod teeth from the Prince Creek Formation (Cretaceous) of Northern Alaska, with speculations on Arctic dinosaur paleoecology. Journal of Vertebrate Paleontology. 20(4), 675-682.
Sankey, Brinkman, Guenther and Currie, 2002. Small theropod and bird teeth from the Late Cretaceous (Late Campanian) Judith River Group, Alberta. Journal of Paleontology. 76(4), 751-763.
Fiorillo, 2008. On the occurence of exceptionally large teeth of Troodon (Dinosauria: Saurischia) from the Late Cretaceous of Northern Alaska. Palaios. 23, 322-328.
Fiorillo, Tykoski, Currie, McCarthy and Flaig, 2009. Description of two partial Troodon braincases from the Prince Creek Formation (Upper Cretaceous), North Slope Alaska. Journal of Vertebrate Paleontology. 29(1), 178-187.
T? sp. (Ryan and Russell, 2001)
Late Campanian, Late Cretaceous
Wapiti Formation, Alberta, Canada
(RTMP 89.55.1008) metatarsal (Ryan and Russell, 2001)
(RTMP 2004.23.3) posterior premaxillary or anterior maxillary tooth (Fanti and Miyashita, 2009)
(UALVP 48749) tooth (5.5x4x2.2 mm) (Torices et al., 2014)
(UALVP 48750) posterior dentary tooth (3.7x3.7x2 mm) (Fanti and Miyashita, 2009)
(UALVP 48753) anterior maxillary tooth (10.8x7.5x3.5 mm) (Fanti and Miyashita, 2009)
(UALVP 48755) premaxillary tooth (4.8x3.1x3.1 mm) (Fanti and Miyashita, 2009)
(UALVP 48757) tooth (8.9x5.9x3.6 mm) (Torices et al., 2014)
(UALVP 48764) tooth (10.8x6.5x3.8 mm) (Torices et al., 2014)
(UALVP 48765) tooth (8.5x5.8x3 mm) (Torices et al., 2014)
(UALVP 48776) tooth (10.5x7.1x3.7 mm) (Torices et al., 2014)
(UALVP 48777) tooth (9.4x7.5x3.6 mm) (Torices et al., 2014)
(UALVP 48779) tooth (11x6.5x3.8 mm) (Torices et al., 2014)
(UALVP 48780) tooth (10.2x6.7x4.8 mm) (Torices et al., 2014)
(UALVP 48785) tooth (8.4x6.3x3.3 mm) (Torices et al., 2014)
(UALVP 52599) tooth (Fanti, Currie and Burns, 2015)
(UALVP 53514) tooth (Fanti, Currie and Burns, 2015)
eighteen teeth (Fanti and Miyashita, 2009)
Comments- Torices et al. (2014) could not statistically distinguish teeth from the Wapiti, Dinosaur Park or Horseshoe Canyon Formations.
References- Ryan and Russell, 2001. The dinosaurs of Alberta (exclusive of Aves). in Tanke and Carpenter (eds.). Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie. Indiana University Press, Bloomington, Indiana. pp. 279-297.
Fanti and Miyashita, 2009. A high latitude vertebrate fossil assemblage from the Late Cretaceous of west-central Alberta, Canada: Evidence for dinosaur nesting and vertebrate latitudinal gradient. Palaeogeography, Palaeoclimatology, Palaeoecology. 275, 37-53.
Torices, Funston, Kraichy and Currie, 2014. The first appearance of Troodon in the Upper Cretaceous site of Danek Bonebed, and a reevaluation of troodontid quantitative tooth morphotypes. Canadian Journal of Earth Sciences. 51(11), 1039-1044.
Fanti, Currie and Burns, 2015. Taphonomy, age, and paleoecological implication of a new Pachyrhinosaurus (Dinosauria: Ceratopsidae) bonebed from the Upper Cretaceous (Campanian) Wapiti Formation of Alberta, Canada. Canadian Journal of Earth Sciences. 52(4), 250-260.
T? sp. (Langston, 1975)
Maastrichtian, Late Cretaceous
St. Mary River Formation, Alberta, Canada
(CMN 10649) tooth (Langston, 1975)
(CMN 10674) partial tooth (Langston, 1975)
References- Langston, 1975. The ceratopsian dinosaurs and associated lower vertebrates from the St. Mary River Formation (Maestrichtian) at Scabby Butte, Southern Alberta. Canadian Journal of Earth Science. 12, 1576-1608.
Ryan and Russell, 2001. The dinosaurs of Alberta (exclusive of Aves). in Tanke and Carpenter (eds.). Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie. Indiana University Press, Bloomington, Indiana. pp. 279-297.
T? sp. nov. (Baszio, 1997)
Late Maastrichtian, Late Cretaceous
Scollard Formation, Alberta, Canada
(RTMP 94.106.1) tooth (Ryan and Russell, 2001)
(UA 109) tooth (Baszio, 1997)
teeth (Ryan and Russell, 2001)
Comments- Baszio (1997) reported UA 109 was similar to Judith River T. formosus in size, but differed in having larger mesial serrations (up to three times wider than distal serrations).
References- Baszio, 1997. Investigations on Canadian dinosaurs: systematic palaeontology of isolated dinosaur teeth from the Latest Cretaceous of south Alberta, Canada. Courier Forschungsinstitut Senckenberg. 196, 33-77.
Ryan and Russell, 2001. The dinosaurs of Alberta (exclusive of Aves). in Tanke and Carpenter (eds.). Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie. Indiana University Press, Bloomington, Indiana. pp. 279-297.
T? sp. (Estes, Berberian and Mesozoely, 1969)
Late Maastrichtian, Late Cretaceous
Hell Creek Formation, Montana, South Dakota, US
(FMNH PR2901) tooth (5.9x2.8x1.3 mm) Gates, Zanno and Makovicky, 2015)
(MCZ 3694) tooth (Estes, Berberian and Mesozoely, 1969)
(UCMP 186856) tooth (UCMP online)
(UCMP 186868) teeth (UCMP online)
(UCMP 186873) tooth (UCMP online)
(UCMP 186885) teeth (UCMP online)
(UCMP 186904) tooth (UCMP online)
(UCMP 187057) tooth (UCMP online)
(UCMP 187168-187174) seven teeth (UCMP online)
(UCMP 187178) tooth (UCMP online)
(UCMP 187184) tooth (UCMP online)
(UCMP 187186) tooth (UCMP online)
(UCMP 214060-214062) three teeth (UCMP online)
teeth (Stenerson and O'Conner, 1994)
material (Triebold and Russell, 1995; Triebold, 1997)
material (Jacobson and Sroka, 1998)
four teeth (Larson, Nellermoe and Gould, 2003)
teeth and elements (DePalma, 2010)
Comments- Estes et al. (1969) referred MCZ 3694 to Coeluridae, while Stenerson and O'Conner (1994) called their teeth Saurornithoides sp.. None have been described yet, though the UCMP specimens were identified as Troodon by Sankey. Gates et al. (2015) noted FMNH PR2901 resembles Pectinodon except for its prominent mesial keel.
References- Estes, Berberian and Mesozoely, 1969. Lower vertebrates from the Late Cretaceous Hell Creek Formation, McCone County, Montana. Breviora. 337, 1-33.
Stenerson and O'Conner, 1994. The Late Cretaceous Hell Creek Formation of Northwestern South Dakota and its Fauna. MAPS Digest. 17(4), 108-120.
Triebold and Russell, 1995. A new small dinosaur locality in the Hell Creek Formation: Journal of Vertebrate Paleontology. 15(3), 57A.
Triebold, 1997. The Sandy Site: Small Dinosaurs from the Hell Creek Formation of South Dakota. in Wolberg, Stump and Rosenberg (eds). Dinofest International, Proceedings of a Symposium sponsered by Arizona State University. A Publication of The Academy of Natural Sciences. 245-248.
Jacobson and Sroka, 1998. Preliminary assement of a Hell Creek Dinosaurian Fauna from sites in Corson County, South Dakota. Journal of Vertebrate Paleontology. 18(3), 53A.
Larson, Nellermoe and Gould, 2003. A study of theropod teeth from a low-species-density hadrosaur bone bed in the Lower Hell Creek Formation in Carson, Co., S.D.. Journal of Vertebrate Paleontology. 23(3), 70A-71A.
DePalma, 2010. Geology, taphonomy, and paleoecology of a unique Upper Cretaceous bonebed near the Cretaceous-Tertiary boundary in South Dakota. Masters thesis, University of Kansas. 227 pp.
Gates, Zanno and Makovicky, 2015. Theropod teeth from the upper Maastrichtian Hell Creek Formation "Sue" Quarry: New morphotypes and faunal comparisons. Acta Palaeontologica Polonica. 60(1), 131-139.
T? sp. (Stokosa, 2005)
Maastrichtian, Late Cretaceous
Fox Hills Formation, South Dakota, US
Material- (KUVP 67265) (two individuals) (~1.3 m) incomplete femur (~160 mm), incomplete tibia (Brewer, 2016)
(~.85 m) incomplete femur (~100 mm), incomplete tibia (Brewer, 2016)
(SDSM 14518) dentary tooth (Stokosa, 2005)
Comments- SDSM 14518 was identified by Stoksad (2005) as Troodon cf. formosus. Its macroscopic structure has not been described.
KUVP 67265 was found in 1980 and "tentatively identified as Troodon formosus in the absence of skull material" by Brewer (2016) in an SVP abstract.
References- Stokosa 2005. Enamel microstructure variation within the Theropoda. In Carpenter (ed.). The Carnivorous Dinosaurs. 163-178.
Brewer, 2016. New specimens of Troodon formosus hind limbs from the Fox Hills Formation of South Dakota. Journal of Vertebrate Paleontology. Program and Abstracts, 104.
T? sp. (Wroblewski, 1998)
Late Maastrichtian, Late Cretaceous
Ferris Formation, Wyoming, US
Reference- Wroblewski, 1998. Changing paleoenvironments and paleofaunas across the K-T boundary, Ferris Formation, Southcentral Wyoming. Tate Geological Museum, Casper College, Casper Wyoming. Tate ’98. Life in the Cretaceous. 53-70.
T? sp. (Hall, 1991)
Late Campanian, Late Cretaceous
Fossil Forest Member of the Fruitland Formation, New Mexico, US
Material- (KUVP 96932) tooth
References- Hall, 1991. Lower vertebrate paleontology of the upper Fruitland Formation, Fossil Forest area, New Mexico, and implications for Late Cretaceous terrestrial biostratigraphy. Masters Thesis. University of Kansas. 126 pp.
Williamson and Brusatte, 2014. Small theropod teeth from the Late Cretaceous of the San Juan Basin, Northwestern New Mexico and their implications for understanding Latest Cretaceous dinosaur evolution. PLoS ONE. 9(4), e93190.
T? sp. nov. (Wel and Williamson, 2000; described by Williamson and Brusatte, 2014)
Late Maastrichtian, Late Cretaceous
Naashoibito Member of Ojo Alamo Formation, New Mexico, US
Material- (NMMNH P-22566; = UNM FKK-014) tooth (6.8x5.3x2.6 mm) (Williamson and Brusatte, 2014)
(NMMNH P-32746) tooth (Williamson and Brusatte, 2014)
(NMMNH P-32772) tooth (8.4x6x3.3 mm) (Williamson and Brusatte, 2014)
(NMMNH P-32784) tooth (Williamson and Brusatte, 2014)
(NMMNH P-33520) tooth (?x?x3.1 mm) (Williamson and Brusatte, 2014)
(NMMNH P-33521) tooth (3.9x3.3x1.9 mm) (Williamson and Brusatte, 2014)
(NMMNH P-33901) tooth (Williamson and Brusatte, 2014)
(SMP VP-3341) tooth (Jasinski, Sullivan and Lucas, 2011)
Comments- Williamson and Brusatte (2014) found these to be statistically different from Dinosaur Park specimens.
References- Weil and Williamson, 2000. Diverse Maastrichtian terrestrial vertebrate fauna of the Naashoibito Member, Kirtland Formation (San Juan Basin, New Mexico) confirms “Lancian” faunal heterogeneity in western North America. Geological Society of America Abstracts with Programs. 32, A-498.
Williamson, 2001. Dinosaurs from microvertebrate sites in the Upper Cretaceous Fruitland and Kirtland Formations, San Juan Basin, New Mexico. 2001 GSA abstracts.
Jasinski, Sullivan and Lucas, 2011. Taxonomic composition of the Alamo Wash local fauna from the Upper Cretaceous Ojo Alamo Formation (Naashoibito Member), San Juan Basin, New Mexico. In Sullivan, Lucas and Spielmann (eds.). Fossil Record 3. New Mexico Museum of Natural History and Science Bulletin. 53, 216-271.
Williamson and Brusatte, 2014. Small theropod teeth from the Late Cretaceous of the San Juan Basin, Northwestern New Mexico and their implications for understanding Latest Cretaceous dinosaur evolution. PLoS ONE. 9(4), e93190.
T? sp. (Langston, Standhardt and Stevens, 1989)
Late Maastrichtian, Late Cretaceous
Lower Javelina Formation, Texas, US
Reference- Langston, Standhardt and Stevens, 1989. Fossil vertebrate collecting in the Big Bend - History and retrospective. in Vertebrate Paleontology, Biostratigraphy and Depositional Environments, Latest Cretaceous and Tertiary, Big Bend Area, Texas. Guidebook Field Trip Numbers 1 a, B, and 49th Annual Meeting of the Society of Vertebrate Paleontology, Austin, Texas, 29 October - 1 November 1989. 11-21.
T? sp. (Montellano, Monroy, Hernandez-Rivera and Torres, 2009)
Late Campanian, Late Cretaceous
Aguja Formation, Mexico
Material- teeth
Reference- Montellano, Monroy, Hernandez-Rivera and Torres, 2009. Late Cretaceous microvertebrate fauna from the Northern state of Coahuila, Mexico. Journal of Vertebrate Paleontology. 29(3), 151A.
T? sp. (Hernandez-Rivera, 1997)
Late Campanian, Late Cretaceous
El Gallo Formation, Mexico
Material- (LACM 42637/HJG 689) tooth (Hilton, 2003)
(42675/HJG 696) tooth (Hilton, 2003)
Comments- These were identified as Saurornithoides by Hilton (2003).
References- Hernandez-Rivera, 1997. Mexican Dinosaurs. in Currie and Padian (eds). Encyclopedia of Dinosaurs. Academic Press. 433-437.
Hilton, 2003. Dinosaurs and other Mesozoic reptiles of California. University of California Press. 318pp.

Albertavenator Evans, Cullen, Larson and Rego, 2017
A. curriei Evans, Cullen, Larson and Rego, 2017
Early Maastrichtian, Late Cretaceous
Horsethief Member of the Horseshoe Canyon Formation, Alberta, Canada
Holotype- (RTMP 93.105.1) incomplete frontal (46.8 mm)
Paratype- (RTMP 96.5.8) incomplete frontal
Referred- ?(RTMP 74.1.1) tooth (6.3x4.6x2.5 mm) (Larson and Currie, 2013)
?(RTMP 74.1.2) tooth (8.4x6.2x3.4 mm) (Larson and Currie, 2013)
?(RTMP 83.12.11) anterior dentary, four teeth (Currie, 1987)
?(RTMP 83.45.5) tooth (7.5x5.7x3.2 mm) (Larson and Currie, 2013)
?(RTMP 83.45.6) tooth (7.4x5.9x3.5 mm) (Larson and Currie, 2013)
?(RTMP 85.12.2) tooth (4.1x3.5x1.7 mm) (Larson and Currie, 2013)
?(RTMP 85.30.32) tooth (5.4x3.1x1.4 mm) (Larson and Currie, 2013)
?(RTMP 85.31.19) tooth (6.6x5.3x2.8 mm) (Larson and Currie, 2013)
?(RTMP 87.12.14) tooth (7.8x5.3x2.8 mm) (Larson and Currie, 2013)
?(RTMP 87.12.19) tooth (7.4x6.1x3.3 mm) (Larson and Currie, 2013)
?(RTMP 88.96.2) tooth (8.4x6.3x3.3 mm) (Larson and Currie, 2013)
?(RTMP 88.96.7) tooth (8.9x6.3x3.1 mm) (Larson and Currie, 2013)
?(RTMP 89.125.14) tooth (4.5x2.4x2 mm) (Larson and Currie, 2013)
?(RTMP 90.82.24) tooth (7.8x6x3.3 mm) (Larson and Currie, 2013)
?(RTMP 90.82.25) tooth (4.9x3.4x1.6 mm) (Larson and Currie, 2013)
?(RTMP 90.82.26) tooth (7.3x5.5x3.1 mm) (Larson and Currie, 2013)
?(RTMP 93.12.13) tooth (7x5.53.3 mm) (Larson and Currie, 2013)
?(RTMP 94.9.4) tooth (7.4x5.7x2.8 mm), tooth (6.1x5.5x2.8 mm) (Larson and Currie, 2013)
?(RTMP 95.2.23) tooth (6.2x5.5x2.5 mm) (Larson and Currie, 2013)
?(RTMP 96.5.8) (Eberth et al., 2013)
?(RTMP 96.5.29) (Eberth et al., 2013)
?(RTMP 96.5.30) (Eberth et al., 2013)
?(RTMP 96.29.29) posterior maxillary tooth (Ryan, Currie, Gardner, Vickaryous and Lavigne, 1998)
?(RTMP 97.7.3) tooth (7x5.5x3.2 mm) (Larson and Currie, 2013)
?(RTMP 97.39.3) posterior dentary tooth (Ryan, Currie, Gardner, Vickaryous and Lavigne, 1998)
?(RTMP 97.39.5) dentary tooth (Ryan, Currie, Gardner, Vickaryous and Lavigne, 1998)
?(RTMP 97.39.7) posterior premaxillary or anterior maxillary tooth (Ryan, Currie, Gardner, Vickaryous and Lavigne, 1998)
?(RTMP 97.77.4) tooth (7x5.6x3.4 mm) (Larson and Currie, 2013)
?(RTMP 98.63.43) tooth (10.7x6.1x3.6 mm) (Larson et al., 2010)
?(RTMP 98.68.156) tooth (8.5x6.4x3.2 mm), tooth (7.6x5.8x3 mm), tooth (8.1x5.6x3.2 mm) (Larson and Currie, 2013)
?(RTMP 99.50.114) tooth (6.8x5.6x3.7 mm) (Larson et al., 2010)
?(RTMP 99.50.115) tooth (10.7x5.8x3.7 mm) (Larson et al., 2010)
?(RTMP 2000.45.10) tooth (Larson et al., 2010)
?(RTMP 2000.45.24) tooth (4.4x3.6x2.2 mm) (Larson et al., 2010)
?(RTMP 2000.45.41) tooth (Larson et al., 2010)
?(RTMP 2000.45.90) tooth (5.2x3.5x2 mm) (Larson et al., 2010)
?(RTMP 2000.45.91) tooth (10x5.4x3.4 mm) (Larson et al., 2010)
?(RTMP 2001.45.80) tooth (12.1x7x4.1 mm) (Larson et al., 2010)
?(RTMP 2001.45.81) tooth (6.6x4.8x2.8 mm) (Larson et al., 2010)
?(RTMP 2002.45.48) tooth (7.7x5.6x? mm) (Larson et al., 2010)
?(RTMP 2003.45.57) tooth (Larson et al., 2010)
?(RTMP 2003.45.58) tooth (7.1x5x2.7 mm) (Larson et al., 2010)
?(RTMP 2003.34.1) tooth (Larson et al., 2010)
?(RTMP 2009.122.1) tooth (9.4x6.3x3.7 mm) (Larson and Currie, 2013)
?(RTMP coll.) six teeth (Baszio, 1997)
?(RTMP coll.) nine premaxillary teeth, thirty-nine maxillary teeth, thirteen dentary teeth (Ryan, Currie, Gardner, Vickaryous and Lavigne, 1998)
?(RTMP or UALVP coll.) metatarsal (Eberth and Currie, 2010)
?(UALVP 48639) tooth (9.5x?x2.8 mm), tooth (9.3x6x3.3 mm), tooth (9.5x6.2x3.7 mm) (Torices et al., 2014)
?(UALVP 53921) tooth (10x6.2x3.7 mm) (Torices et al., 2014)
?(UALVP 55456) tooth (7.4x5.7x3.3 mm) (Torices et al., 2014)
?(UALVP 55489) tooth (10x6.2x3.6 mm) (Torices et al., 2014)
? partial braincase (Morhardt et al., 2013)
Diagnosis- (after Evans et al., 2017) primary supraciliary foramen truncated anteriorly by lacrimal contact; superficial (ectocranial) surface of frontal proportionally shorter than other troodontids, length to width ratio less than 1.3; frontoparietal contact in which an enlarged lappet of the frontal extends medially to extensively overlap the lateral region of the interfrontal process of the parietal.
Comments- Currie (1987) described a dentary with teeth that can be referred to Troodon because of its extensive mandibular symphysis. Although Currie et al. (1990) state Horseshoe Canyon Formation teeth are essentially identical to Judith River teeth, Baszio (1997) notes they are are generally smaller than Dinosaur Park (Judith River) T. formosus, but identical in morphology. Ryan et al. (1998) state they could not distinguish Horseshoe Canyon teeth from Judith River teeth, but referred to the former as Troodon sp. due to the stratigraphic difference. Similarly, Torices et al. (2014) could not distinguish Horseshoe Canyon and Dinosaur Park teeth statistically. However, Larson and Currie (2013) found "troodontid teeth from the Horseshoe Canyon Formation are distinct from the Dinosaur Park Formation teeth." Morhardt et al. (2013) examined Dinosaur Park and Two Medicine braincases and found "two distinct morphologies associated with the occipital sinus, in one case being 'peaked' (dorsally extended, mediolaterally compressed) and the other case being 'rounded' (dorsal surface gently curves, shows no dorsal extension, and is not mediolaterally compressed)." The peaked morphology was said to be more similar to Zanabazar. Most recently, Evans et al. (2017) found Dinosaur Park and Judith River teeth largely overlapped the morphospace of Horseshoe Canyon teeth, though the spaces that ignore the 5% of outliers have a more limited degree of overlap. They also agreed with Currie that Dinosaur Park and Horseshoe Canyon dentaries cannot be distinguished, but described two Horseshoe Canyon frontals as the types of their new taxon Albertavenator curriei based on several difference from Dinosaur Park frontals. Discovered in 1993, the holotype was listed along with the paratype as Troodon formosus elements by Eberth et al. (2013). The lack of any associated specimens means that only the frontals can be confidently assigned to Albertavenator, as it is possible multiple troodontid taxa coexisted in the formation.
References- Currie, 1987. Bird-like characteristics of the jaws and teeth of troodontid theropods (Dinosauria, Saurischia). Journal of Vertebrate Paleontology. 7, 72-81.
Currie, Rigby and Sloan, 1990. Theropod teeth from the Judith River Formation of southern Alberta, Canada. in Carpenter and Currie (eds.). Dinosaur Systematics: Perspectives and Approaches. Cambridge University Press, New York. pp. 107-125.
Baszio, 1997. Investigations on Canadian dinosaurs: systematic palaeontology of isolated dinosaur teeth from the Latest Cretaceous of south Alberta, Canada. Courier Forschungsinstitut Senckenberg. 196, 33-77.
Ryan, Currie, Gardner and Livigne, 1997. Baby hadrosaurid material associated with an unusually high abundance of troodontid teeth from the Horseshoe Canyon Formation (Early Maastrichtian), Alberta, Canada. Journal of Vertebrate Paleontology. 17(3), 72A.
Ryan, Currie, Gardner, Vickaryous and Lavigne, 1998. Baby hadrosaurid material associated with an unusually high abundance of Troodon teeth from the Horseshoe Canyon Formation, Upper Cretaceous, Alberta, Canada. Gaia. 15, 123-133.
Evans, Lam, Maddin and Conacher, 2003. Taphonomy of the Prehistoric Park Quarry, Horseshoe Canyon Formation, Drumheller, Alberta. Alberta Palaeontological Society, Seventh Annual Symposium, "Fossils in Motion" Abstracts. 25-28.
Eberth and Currie, 2010. Stratigraphy, sedimentology, and taphonomy of the Albertosaurus bonebed (upper Horseshoe Canyon Formation; Maastrichtian), southern Alberta, Canada. Canadian Journal of Earth Sciences. 47(9), 1119-1143.
Larson, Brinkman and Bell, 2010. Faunal assemblages from the upper Horseshoe Canyon Formation, an early Maastrichtian cool-climate assemblage from Alberta, with special reference to the Albertosaurus sarcophagus bonebed. Canadian Journal of Earth Sciences. 47(9), 1159-1181.
Eberth, Evans, Brinkman, Therrien, Tanke, Russell and Sues, 2013. Dinosaur biostratigraphy of the Edmonton Group (Upper Cretaceous), Alberta, Canada: Evidence for climate influence. Canadian Journal
of Earth Sciences. 50(7), 701-726.
Larson and Currie, 2013. Multivariate analyses of small theropod dinosaur teeth and implications for paleoecological turnover through time. PloS ONE. 8(1), e54329.
Morhardt, Ridgely, Varricchio and Witmer, 2013. New studies of braincase anatomy, brain size, and brain structure in the Late Cretaceous theropod Troodon formosus (Dinosauria: Saurischia) based on CT scanning and 3D visualization. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 180.
Torices, Funston, Kraichy and Currie, 2014. The first appearance of Troodon in the Upper Cretaceous site of Danek Bonebed, and a reevaluation of troodontid quantitative tooth morphotypes. Canadian Journal of Earth Sciences. 51(11), 1039-1044.
Evans, Cullen, Larson and Rego, 2017. A new species of troodontid theropod (Dinosauria: Maniraptora) from the Horseshoe Canyon Formation (Maastrichtian) of Alberta, Canada. Canadian Journal of Earth Sciences. 54, 813-826.

Hypnovenator Kubota, Kobayashi and Ikeda, 2024
H. matsubaraetoheorum Kubota, Kobayashi and Ikeda, 2024
= Hypnovenator "sasayamaensis" Kubota, Kobayashi and Ikeda, 2024 online
Etymologies- "The genus name derives from "hypno", refers to "sleep" in ancient Greek, and "venator", means "hunter" in Latin. The specific name, "matsubaraetoheorum", honors Mrs. Kaoru Matsubara and Takaharu Ohe, who are the first discoverers of a block including a part of Hypnovenator matsubaraetoheorum holotype specimen."
"The specific name, "sasayama", refers to previous name of a city placed in the eastern region of Hyogo Prefecture, from where the holotype specimen was collected. It also refers to an amateur group "Association to Study the Sasayama Group", to which the two discovers belong."
Early-Middle Albian, Early Cretaceous
Ohyamashimo Formation, Nishikosa, Tambasasayama City, Hyogo Prefecture, Japan
Holotype- (MNHAH D1033340) two left dorsal rib fragments, thirty-eight gastralia, posterior distal caudal vertebra, anterior distal caudal vertebra, distal chevron (~13.8 mm anteropost), incomplete left humerus (13.1 mm trans distally), left radius (73.4 mm), left ulna (76.1 mm), left semilunate carpal (7.5 mm trans), left metacarpal I (14.3 mm), distal right metacarpal I, left phalanx I-1 (31.6 mm), left manual ungual I (19.7 mm), left metacarpal II (35.8 mm), left phalanx II-1 (22.0 mm), (phalanx II-2 ~28 mm) incomplete left manual ungual II, left metacarpal III (34.4 mm), left phalanx III-1 (8.3 mm), left phalanx III-2 (9.0 mm), left phalanx III-3 (22.8 mm), left manual ungual III (13.2 mm), manual claw sheath, distal left femur (20.1 mm trans), distal right tibia, incomplete left tibia (16.9 mm trans distally), incomplete left fibula, left astragalocalcaneum (16.9 mm trans), distal right astragalocalcaneum, proximal left metatarsal II, proximal right metatarsal II fragment, distal right pedal ungual II, proximal left metatarsal III, incomplete right phalanx III-1, right phalanx III-2 (15.3 mm), right phalanx III-3 (15.4 mm), right pedal ungual III (11.9 mm), proximal left metatarsal IV, proximal right metatarsal IV fragment, distal right phalanx IV-1, right phalanx IV-2 (12.7 mm), right phalanx IV-3 (11.2 mm), right phalanx IV-4 (11.4 mm), right pedal ungual IV (11.7 mm), left metatarsal V (~35.5 mm)
Diagnosis- (after Kubota et al., 2024) pair of proximodistally extended depressions on proximodorsal surface of manual phalanx I-1; long dorsal and ventral proximal lips on manual phalanx III-2 for tight articulation with phalanx III-1; medial epicondylar ridge on distal femur; distorted distal condyles with widely convex distoventral margin in side view on pedal phalanx III-3.
Comments- Discovered in September 2010 and July 2011. The species name "sasayamaensis" was used in the preprint of the article. Kubota et al. (2024) state "The length of manual phalanx II-2 is estimated based on the distance between the distal end of phalanx II-1 and the proximal articular surface of phalanx II-3."
Kubota et al. (2024) used a version of Mortimer's maniraptoromorph analysis to recover Hypnovenator sister to Gobivenator. Scoring it in an updated version moves it sister to Talos + Linhevenator.
References- Kubota, Kobayashi and Ikeda, 2024 online. Early Cretaceous troodontine troodontid (Dinosauria: Theropoda) from the Ohyamashimo Formation of Japan reveals the early evolution of Troodontinae. Research Square preprint. DOI: 10.21203/rs.3.rs-4459611/v1
Kubota, Kobayashi and Ikeda, 2024. Early Cretaceous troodontine troodontid (Dinosauria: Theropoda) from the Ohyamashimo Formation of Japan reveals the early evolution of Troodontinae. Scientific Reports. 14:16392.

Linhevenator Xu, Tan, Sullivan, Han and Xiao, 2011
L. tani Xu, Tan, Sullivan, Han and Xiao, 2011
Campanian, Late Cretaceous
Wulansuhai Formation, Inner Mongolia, China
Holotype- (LH V0021) (~23 kg adult) incomplete skull (~220 mm), premaxillary tooth, partial surangular, lateral tooth, six incomplete anterior or mid dorsal vertebrae (~29 mm), incomplete scapula (~170 mm), incomplete humerus (~95 mm), incomplete ischium, femur (~240 mm), metatarsal I (~25 mm), incomplete phalanx I-1 (~23 mm), incomplete pedal ungual I (~31 mm), incomplete metatarsal II (~120 mm), incomplete phalanx II-1 (28 mm), incomplete phalanx II-2 (14 mm without heel), incomplete pedal ungual II (~50 mm), metatarsal III (150 mm), phalanx III-1 (~40 mm), incomplete phalanx III-2 (~29 mm), incomplete phalanx III-3 (~25 mm), incomplete pedal ungual III (~31 mm), incomplete metatarsal IV (~145 mm), phalanx IV-1 (~35 mm), phalanx IV-2 (~18 mm), incomplete phalanx IV-3 (~16 mm), incomplete phalanx IV-4 (~17 mm), incomplete pedal ungual IV (~25 mm)
Diagnosis- (after Xu et al., 2011) jugal with lateral flange; surangular crest anteroventrally oriented; presence of medial expansion near distal end of femur; wide longitudinal groove present along distal third of dorsal surface of metatarsal III.
Comments- Discovered in 2009. This was included in a version of Senter's TWiG coelurosaur analysis and found to be a derived troodontid in a polytomy with Troodon and Saurornithoides+Zanabazar.
Reference- Xu, Tan, Sullivan, Han and Xiao, 2011. A short-armed troodontid dinosaur from the Upper Cretaceous of Inner Mongolia and its implications for troodontid evolution. PLoS ONE. 6(9), e22916.

Talos Zanno, Varricchio, O’Connor, Titus and Knell, 2011
T. sampsoni Zanno, Varricchio, O’Connor, Titus and Knell, 2011
Late Campanian, Late Cretaceous
Kaiparowitz Formation, Utah, US
Holotype- (UMNH VP 19479) (4 year old subadult) mid dorsal vertebra (22.86 mm), partial mid dorsal centrum, partial posterior dorsal centrum, dorsal fragments, first sacral centrum (19.98 mm), caudal fragment, proximal chevron fragments, radial fragment, ulna (93.4 mm), partial ilium, ilial fragments, incomplete pubes, incomplete ischia, partial femur, partial tibia, partial fibula, astragalus (one fragmentary), calcanea (one fragmentary), metatarsal I, phalanx I-1 (18.7 mm), pedal unguals I (22.89 mm), metatarsals II (158.86 mm), phalanx II-1 (32.29 mm), phalanges II-2 (22.29 mm), pedal ungual II, partial metatarsals III, phalanges III-1 (35.58 mm), phalanges III-2 (25.96 mm), phalanges III-3 (25.68 mm), pedal ungual III, metatarsals IV (175.88 mm), phalanges IV-1, phalanges IV-2, phalanx IV-3 (17.12 mm), phalanges IV-4 (18.02 mm), pedal unguals IV (18.45 mm)
Referred- ?(ALF coll.) teeth (Zanno et al., 2011)
?(OMNH 21958) tooth (Parrish, 1999)
?(RAM coll.) teeth (Zanno et al., 2013)
?(UCM 83253) tooth (Parrish, 1999)
?(UCM 8659; in part) tooth (Parrish, 1999)
?(UCMP 149171) partial squamosals, parietals, basioccipital, proximal tibia, fragmentary metatarsals, pedal phalanges, pedal unguals (Zanno et al., 2009; described by Zanno et al., 2011)
?(UMNH VP 11806) dentary tooth (Zanno et al., 2011)
?(UMNH VP 12507) maxillary tooth (Zanno et al., 2011)
?(UMNH VP 16303) frontal (65.2 mm) (Zanno, 2007; described by Zanno et al., 2011)
?(UMNH VP coll.) distal caudal vertebra (Zanno et al., 2009; described by Zanno et al., 2011)
?(UMNH VP coll.) teeth (Zanno et al., 2011)
Diagnosis- (after Zanno et al., 2011) acetabular margin of ischium strongly concave dorsally; notch between lateral condyle and ascending process of astragalus in lateral view, poorly developed; intercondylar bridge of astragalus hyperconstricted; proximal groove separating astragalar body and ascending process craniocaudally wide and v-shaped; cranioproximal groove on astragalar condyles absent; astragalar condyles subequal in cranial extent; shaft of metatarsal II markedly compressed (midshaft length-to-transverse width ratio 38.8); metatarsal III distally ginglymoid; pronounced, rounded tab on dorsolateral aspect of metatarsal III proximal to distal condyle; distal corner of lateral collateral ligament pit on metatarsal IV with small protuberance, creating rounded depression between extensor aspects of distal condyles.
Comments- Discovered in 2008 and initially announced by Zanno et al. (2009). The holotype was included in a version of Norell et al.'s 2000 troodontid analysis and found to be at least as derived as Byronosaurus.
Parrish and Eaton (1991) list troodontid remains, which Hutchison et al. (1997) lists as Troodon sp.. The partial skeleton UCMP 149171 was discovered in 1994. Zanno et al. (2009) mistakenly cite it as UCMP 143270, which is a Parasaurolophus specimen. Zanno et al. (2011) briefly describe the remains and note they may be referrable to the contemporaneous Talos. Zanno (2007) first mentioned UMNH VP 16303 as a taxon distinct from Troodon, though it was later relegated to Troodontidae indet.. Evans et al. (2017) find it to be outside the range of variation of Dinosaur Park frontals (Latenivenatrix/Stenonychosaurus) and distant from Albertavenator from the Hoseshoe Canyon Formation as well. The tooth UMNH VP 12507 has large distal serrations (12) and no mesial serrations.
References- Parrish and Eaton, 1991. Diversity and evolution of dinosaurs in the Cretaceous of the Kaipirowits plateau, Utah. Journal of Vertebrate Paleontology. 11(3), 50A.
Hutchison, Eaton, Holroyd and Goodwin, 1997. Larger vertebrates of the Kaiparowits Formation (Campanian) in the Grand Staircase-Escalante National Monument and adjacent areas. In Hill (ed.). Learning from the Land: Grand Staircase-Escalante National Monument Science Symposium Proceedings. U.S. Department of the Interior, Bureau of Land Management. 391-398.
Parrish, 1999. Dinosaur teeth from the Upper Cretaceous (Turonian-Judithian) of southern Utah. In Gillette (ed.). Vertebrate Paleontology in Utah. Utah Geological Survey, Miscellaneous Publication. 99-1, 319-321.
Zanno, 2007. A new troodontid theropod from the Late Campanian Kaiparowits Formation, southern Utah. Journal of Vertebrate Paleontology. 27(3), 170A-171A.
Zanno, Varricchio, Titus, Wilkins and Knell, 2009. A new troodontid (Theropoda: Paraves) specimen from the Upper Campanian Kaiparowitz Formation, Southern Utah: Estimating the taxonomic diversity of North American Troodontidae. Journal of Vertebrate Paleontology. 29(3), 205A.
Zanno, Varricchio, O’Connor, Titus and Knell, 2011. A new troodontid theropod, Talos sampsoni gen. et sp. nov., from the Upper Cretaceous western interior basin of North America. PLoS ONE. 6(9), e24487.
Zanno, Loewen, Farke, Kim, Claessens and McGarrity, 2013. Late Cretaceous theropod dinosaurs of southern Utah. In Titus and Loewen (eds.). Advances in Late Cretaceous Western Interior Basin Paleontology and Geology. Indiana Press. 504-525.
Evans, Cullen, Larson and Rego, 2017. A new species of troodontid theropod (Dinosauria: Maniraptora) from the Horseshoe Canyon Formation (Maastrichtian) of Alberta, Canada. Canadian Journal of Earth Sciences. 54, 813-826.