List of archosaurs of the Chinle Formation
Introduction The Chinle Formation is an Upper Triassic continental geologic formation in the western United States which has yielded fossils of  many archosaurs: a group of vertebrates that includes crocodiles, pterosaurs, dinosaurs (including birds), and other extinct relatives. This is a list of all archosaurs from the formation, including suchians (crocodilian relatives) and avemetatarsalians (dinosaurs, pterosaurs, and their relatives), as well as the abundant crocodilian-like phytosaurs, which may either be true archosaurs or very close relatives of Archosauria.
Phytosaurs '''Phytosaurs of the Chinle Formation''' Genus Species State Member Abundance Notes Images''Leptosuchus''''L. crosbiensis''* Arizona* Sonsela* Blue Mesa* Mesa Redondo''Smilosuchus adamanensis''''Smilosuchus gregorii''''Paleorhinus''Protome batalaria''''Smilosuchus'' ''S. adamanensis''* Arizona* Sonsela* Blue Mesa* Mesa RedondoKnown from a single skullPreviously referred to ''Leptosuchus'', actually referable to ''Smilosuchus''. ''S. gregorii''*Arizona* Sonsela* Blue Mesa* Mesa RedondoKnown from a handful of skulls.A basal leptosuchomorph.''S. lithodendrorum''*Arizona*Blue MesaKnown from only one skull.Previously considered synonymous with ''S. adamanensis''.cf. ''Paleorhinus''Indeterminate* Arizona* Mesa Redondo''Machaeroprosopus''''M. buceros''* Arizona* Owl Rock* Petrified Forest* Sonsela''M. mccauleyi''* Arizona* Owl Rock* Petrified Forest* Sonsela''M. pristinus''* Arizona* Owl Rock* Petrified Forest* Sonsela''Pravusuchus''''P. hortus''* Arizona* SonselaThree skulls.A leptosuchomorph phytosaur closely related to Mystriosuchini or ''Nicrosaurus''.''Protome''''P. batalaria''* Arizona* SonselaPartial skull and jaw.A phytosaur originally described as a juvenile ''Leptosuchus'', but probably an unrelated non-leptosuchomorph or mystriosuchin.''Redondasaurus''''R. gregorii''* Arizona* Utah* "Siltstone" / Rock Point* Petrified Forest* Church Rock A large late-surviving mystriosuchin phytosaur closely related to ''Machaeroprosopus'' (formerly known as ''Pseudopalatus''), and often considered a subgenus of that taxon.
Suchians ===Aetosaurs==='''Aetosaurs of the Chinle Formation''' Genus Species State Member Abundance Notes Images''Adamanasuchus''''A. eisenhardtae''* Arizona* Blue MesaOsteoderms and skull and postcranial fragments.A basal desmatosuchine related to ''Calyptosuchus'' and ''Scutarx''. ''Desmatosuchus spurensis''Typothorax coccinarum''''Calyptosuchus''''C. wellesi''* Arizona* Blue MesaCommon, although "non-armor material is comparatively rare".A basal desmatosuchine originally considered a species of ''Stagonolepis''.''Desmatosuchus''''D. spurensis''* Arizona* Blue MesaNumerous osteoderms and other skeletal materialA large desmatosuchin which was fairly common in the lower part of the Chinle Formation. Prior to 2008, fossils of ''D. spurensis'' were listed as the species ''D. haplocerus'', until it was determined that ''D. haplocerus'' was a species name originally based on undiagnostic fossils.''D. smalli''* Arizona* Sonsela?A single lateral osteoderm.A desmatosuchin which is very rare in the Chinle Formation. One of the youngest known occurrences of the genus ''Desmatosuchus''.''Paratypothorax''''P. andressorum''* Arizona* Blue Mesa* SonselaOsteodermsA significant number of researchers feel that the North American material referred to the German ''Paratypothorax'' species ''P. andressorum'' by Hunt and Lucas in 1992 is actually distinct.Indeterminate''Paratypothorax'' sp.' and '''Paratypothorax''-Like Forms'," Irmis (2005) p. 78* Arizona* New Mexico* SonselaOsteoderms and minor postcranial fragments.A paratypothoracin typothoracine known from isolated material similar to more complete specimens from Germany.''Rioarribasuchus''''R. chamaensis''* Arizona* New Mexico* Petrified Forest* SonselaOsteoderms and possible ankle and vertebrae remains.A late-surviving paratypothoracin typothoracine. Originally referred to ''Desmatosuchus'', but later reinterpreted as a relative of ''Paratypothorax'' based on a phylogenetic analysis performed on the remains by Parker in 2003.New genus names were erected independently by Parker (coining the name ''Heliocanthus'') and Lucas et al. (coining the name ''Rioarribasuchus''), prompting an investigation into reports of unethical taxonomic claim-jumping.''Scutarx''''S. deltatylus''* Arizona* SonselaFour partial skeletons including skull fragments.A large basal desmatosuchine based on fossils originally referred to ''"Stagonolepis" (=Calyptosuchus) wellesi'', a close relative. Fossils of ''Scutarx'' represent the highest stratigraphic occurrence of ''Stagonolepis''-like aetosaurs in Petrified Forest National Park.''Stenomyti''''S. huangae''* Colorado* "Red siltstone"Partial skeleton including a well-preserved skull.A small aetosaurine similar to ''Aetosaurus''.''Typothorax''''T. coccinarum''* Arizona* Owl Rock* Petrified Forest* SonselaCommon in the Owl Rock and Petrified Forest Members.A large, wide-bodied typothoracine abundant throughout the Chinle Formation. Almost all of the known Chinlean ''Typothorax'' fossils are isolated whole or fragmentary osteoderms.''Tecovasuchus''''T. chatterjeei''* Arizona* Blue MesaOsteoderms.Previously thought to be more widespread in the formation.''Kryphioparma''''K. caerula''* Arizona* Blue MesaOsteoderms.Described in 2023, probably related to other typothoracines.===Crocodylomorphs=== '''Crocodylomorphs of the Chinle Formation''' Genus Species State Member Abundance Notes Images''Hesperosuchus''''H. agilis''* Arizona* Petrified Forest* Blue Mesa* Mesa RedondoHesperosuchus agilis''''Parrishia''''P. mccreai''* Arizona* Blue Mesa* Mesa Redondo===Other paracrocodylomorphs==='''Paracrocodylomorphs of the Chinle Formation''' Genus Species State Member Abundance Notes Images''Effigia''''E. okeeffeae''* New Mexico * "Siltstone"A six-foot-long shuvosaurid from the ''Coelophysis'' quarry of Ghost Ranch. ''Effigia okeeffeae''''Poposaurus gracilis''''Postosuchus kirkpatricki''''Shuvosaurus inexpectatus''''Poposaurus''''P. gracilis''* Arizona* Blue Mesa* Mesa Redondo''Postosuchus''''P. kirkpatricki''* Arizona* Owl Rock* Petrified Forest* Sonsela* Blue Mesa* Mesa Redondo''Saurosuchus''Indeterminate* Arizona* Blue MesaJaw fragment.Identified from a fossil which has been reinterpreted as an indeterminate "rauisuchian".''Shuvosaurus''''S. inexpectatus''* Arizona* Owl Rock* Petrified Forest* Mesa Redondo''Vivaron''''V. haydeni''* New Mexico* Petrified ForestA large rauisuchid similar to ''Postosuchus''.===Other suchians==='''Miscellaneous suchians of the Chinle Formation''' Genus Species State Member Abundance Notes Images''Acaenasuchus''''A. geoffreyi''* Arizona* Sonsela* Blue Mesa* Mesa RedondoKnown from a handful of isolated osteoderms.A controversial suchian based primarily on osteoderms. Some paleontologists have considered ''Acaenasuchus'' to be juvenile ''Desmatosuchus haplocerus'' scutes, while others considered it a separate genus of small aetosaurs. Most recently it has been reconsidered an aetosauriform related to, but not within, Aetosauria. It is also related to ''Revueltosaurus'' (also from the Chinle) and the armored reptile ''Euscolosuchus'' from Virginia. ''Revueltosaurus''''Revueltosaurus''''Revueltosaurus callenderi''' and '''Revueltosaurus hunti,'''" Irmis (2005) pp. 71-72''R. callenderi''* Arizona* Petrified Forest''R. hunti''* Arizona* Blue Mesa
Avemetatarsalians ===Basal avemetatarsalians==='''Basal Dinosauriforms of the Chinle Formation''' Genus Species State Member Abundance Notes Images''Dromomeron''''D. romeri''* Arizona* Colorado* New Mexico* Petrified Forest (Hayden Quarry #3)* Owl Rock* ‘Red siltstone’A lagerpetid pterosauromorph found at various Ghost Ranch quarries and elsewhere in the Chinle Formation.Dromomeron romeri''Kwanasaurus williamparkeri''''Eucoelophysis''''E. baldwini''* New Mexico* Petrified ForestA silesaurid dinosauriform closely related to the Polish genus ''Silesaurus''.''Kwanasaurus''''K. williamparkeri''* Colorado* "Red siltstone"A silesaurid dinosauriform with adaptations for herbivory.===Dinosaurs======= Sauropodomorphs ====Prosauropod tracks are present in the Redonda, Sloan Canyon, and Sheep Pen Sandstone formations. Possibly the Rock Point Formation as well. Geographically, the tracks are present in New Mexico.==== Theropods and near-relatives ====Theropod tracks have been found in Utah and New Mexico recovered from the Redonda, Sloan Canyon, and Sheep Pen Sandstone formations. Indeterminate theropod remains are stratigraphically present in the Petrified Forest, Bluewater Creek, and Rock Point members of New Mexico. '''Theropods and near-relatives of the Chinle Formation''' Genus Species State Member Abundance Notes Images ''Camposaurus''''C. arizonensis'' * Arizona* Bluewater Creek Formation A coelophysine coelophysidCamposaurus arizonensis''Chindesaurus bryansmalli'' (interpreted as a herrerasaurid)''Coelophysis bauri''Daemonosaurus chauliodus''Tawa hallae'' ''Chindesaurus''''C. bryansmalli''* Arizona* Petrified Forest  A large saurischian alternatively considered a herrerasaurid or a theropod related to ''Tawa hallae''. ''Coelophysis''''C. bauri'' * New Mexico* "Siltstone"''C.'' sp. *Arizona*Petrified ForestOriginally assigned to ''C. bauri'', but likely a different taxon.''C. longicollis''* New Mexico* Petrified ForestNow considered a junior synonym of ''C. bauri''.''C. willistoni''* New Mexico* Petrified ForestNow considered a junior synonym of ''C. bauri''.''Daemonosaurus''''D. chauliodus''* New Mexico* "Siltstone"Skull and neck vertebrae fragments A possible basal theropod with a short skull and enlarged teeth.''Tawa''''T. hallae''* New Mexico* Petrified Forest (Hayden Quarry) A probable basal theropod showing a mosaic of features similar to neotheropods and herrerasaurids.
See also * Paleobiota of the Chinle Formation
Footnotes
References * Ezcurra, M.D. (2006). "A review of the systematic position of the dinosauriform archosaur ''Eucoelophysis baldwini'' Sullivan & Lucas, 1999 from the Upper Triassic of New Mexico, USA." ''Geodiversitas'', '''28'''(4):649-684. * Irmis, R. B. 2005.The vertebrate fauna of the Upper Triassic Chinle Formation in northern Arizona. p. 63-88.in S.J. Nesbitt, W.G. Parker, and R.B. Irmis (eds.) 2005.Guidebook to the Triassic formations of the Colorado Plateau in northern Arizona: Geology, Paleontology, and History. Mesa Southwest Museum Bulletin 9. * Nesbitt, S.J., Irmis, R.B., and Parker, W.G. (2005). "A critical review of the Triassic North American dinosaur record." In Kellner, A.W.A., Henriques, D.D.R., & Rodrigues, T. (eds. ), ''II Congresso Latino-Americano de Paleontologia de Vertebrados, Boletim de Resumos.'' Rio de Janeiro: Museum Nacional/UFRJ, 139. * Sues, H.-D., Nesbitt, S. J., Berman, D. S., and A. C., Henrici. 2011.A late-surviving basal theropod dinosaur from the latest Triassic of North America. Proceedings of the Royal Society B. * Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds. ): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. .