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 of the Chinle Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | State | Member | Abundance | Notes | Images |
| Leptosuchus[1] | L. crosbiensis |
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| Smilosuchus[2] | S. adamanensis |
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| Known from a single skull | Previously referred to Leptosuchus, actually referable to Smilosuchus. | |
| S. gregorii |
|
| Known from a handful of skulls. | A basal leptosuchomorph. | ||
| S. lithodendrorum |
|
| Known from only one skull. | Previously considered synonymous with S. adamanensis. | ||
| cf. Paleorhinus[3] | Indeterminate |
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| Machaeroprosopus[4] | M. buceros |
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| M. mccauleyi |
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| M. pristinus |
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| Pravusuchus[5] | P. hortus |
|
| Three skulls. | A leptosuchomorph phytosaur closely related to Mystriosuchini[6] or Nicrosaurus.[7] | |
| Protome[8] | P. batalaria |
|
| Partial skull and jaw. | A phytosaur originally described as a juvenile Leptosuchus, but probably an unrelated non-leptosuchomorph or mystriosuchin. | |
| Redondasaurus[9] | R. gregorii |
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| A large late-surviving mystriosuchin phytosaur closely related to Machaeroprosopus (formerly known as Pseudopalatus),[10] and often considered a subgenus of that taxon. | ||
| Aetosaurs of the Chinle Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | State | Member | Abundance | Notes | Images |
| Adamanasuchus | A. eisenhardtae |
|
| Osteoderms and skull and postcranial fragments. | A basal desmatosuchine related to Calyptosuchus and Scutarx. | |
| Calyptosuchus[11] | C. wellesi[12] |
|
| Common, although "non-armor material is comparatively rare". | A basal desmatosuchine originally considered a species of Stagonolepis. | |
| Desmatosuchus[13] | D. spurensis[14] |
|
| Numerous osteoderms and other skeletal material | A 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[15] |
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| 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[16] | P. andressorum |
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| Osteoderms | A 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[17] |
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| Osteoderms and minor postcranial fragments. | A paratypothoracin typothoracine known from isolated material similar to more complete specimens from Germany.[18] | ||
| Rioarribasuchus | R. chamaensis |
|
| Osteoderms 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[20] | S. deltatylus |
|
| Four 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 |
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| Partial skeleton including a well-preserved skull. | A small aetosaurine similar to Aetosaurus. | |
| Typothorax[21] | T. coccinarum |
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| Common 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 |
|
| Osteoderms. | Previously thought to be more widespread in the formation. | |
| Kryphioparma | K. caerula |
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| Osteoderms. | Described in 2023, probably related to other typothoracines. | |
| Crocodylomorphs of the Chinle Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | State | Member | Abundance | Notes | Images |
| Hesperosuchus[22] | H. agilis |
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| Parrishia[23] | ||||||
|style="background:#f3e9f3;" |
|style="background:#f3e9f3;" ||style="background:#f3e9f3;" |Following a rediagnosis of the genus and species, only shuvosaurid fossils from the Cooper Canyon Formation are reliably identifiable as Shuvosaurus itself.[25] |-|Vivaron[26] |V. haydeni|
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||A large rauisuchid similar to Postosuchus.|-|}
| Miscellaneous suchians of the Chinle Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | State | Member | Abundance | Notes | Images |
| Acaenasuchus[27] | A. geoffreyi |
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| Known 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.[28] | |
| Revueltosaurus[29] | R. callenderi[30] |
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| R. hunti[31] |
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| Basal Dinosauriforms of the Chinle Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | State | Member | Abundance | Notes | Images |
| Dromomeron | D. romeri |
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| A lagerpetid pterosauromorph found at various Ghost Ranch quarries and elsewhere in the Chinle Formation. | ||
| Eucoelophysis | E. baldwini |
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| A silesaurid dinosauriform closely related to the Polish genus Silesaurus.[32] | ||
| Kwanasaurus[33] | K. williamparkeri |
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| A silesaurid dinosauriform with adaptations for herbivory. | ||
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.[34]
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 |
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| A coelophysine coelophysid | ||
| Chindesaurus | C. bryansmalli |
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| A large saurischian alternatively considered a herrerasaurid or a theropod related to Tawa hallae. | ||
| Coelophysis | C. bauri |
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| C. sp.[36] |
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| Originally assigned to C. bauri, but likely a different taxon. | |||
| C. longicollis |
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| Now considered a junior synonym of C. bauri. | |||
| C. willistoni |
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| Now considered a junior synonym of C. bauri. | |||
| Daemonosaurus | D. chauliodus |
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| Skull and neck vertebrae fragments | A possible basal theropod with a short skull and enlarged teeth. | |
| Tawa | T. hallae |
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| A probable basal theropod showing a mosaic of features similar to neotheropods and herrerasaurids. | ||
]
|style="background:#f3e9f3;" |
|style="background:#f3e9f3;" |Jaw fragment.|style="background:#f3e9f3;" |Identified from a fossil which has been reinterpreted as an indeterminate "rauisuchian".|-|style="background:#f3e9f3;" |Shuvosaurus[25]
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| Paracrocodylomorphs of the Chinle Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | State | Member | Abundance | Notes | Images |
| Effigia | E. okeeffeae |
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| A six-foot-long shuvosaurid from the Coelophysis quarry of Ghost Ranch. | ||
| Poposaurus[23] | P. gracilis |
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| Postosuchus[24] | P. kirkpatricki |
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| Saurosuchus[25] | ||||||