Popo Agie Formation
Stratigraphic range: Late Triassic
TypeGeological formation
Unit ofChugwater Group
OverliesGartra Formation
Location
RegionNorth America
CountryUnited States

The Popo Agie Formation is a Triassic geologic formation that crops out in western Wyoming, western Colorado, and Utah. It was deposited during the Late Triassic in fluvial (river) and lacustrine (lake) environments that existed across much of what is now the American southwest.[1] Fragmentary fossils of prehistoric reptiles and amphibians, including pseudosuchian reptiles and temnospondyl amphibians, have been discovered in the Popo Agie Formation. Dinosaur remains are also among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.[2]

Paleobiota

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Amphibians

Taxon Member Material Notes Images

Apachesaurus sp.

Complete skull

A metoposaurid temnospondyl; specimen from the Popo Agie Formation was originally described as Anaschisma sp. and later Eupelor browni[3]

Koskinonodon perfecta

Complete skull

A metoposaurid temnospondyl; specimen from the Popo Agie Formation was originally described as Borborophagus wyomingensis[3]

Metoposauridae indet.

Complete skull

Specimen was originally described as Anaschisma browni[3]

Reptiles

Taxon Member Material Notes Images

Heptasuchus clarki

UW 11562, a partial skull and postcranial skeleton; UW 11563 through UW 11565, partial postcranial remains; both from Big Horn Mountains, Wyoming[4]

A rauisuchian

(in background)

Beesiiwo cooowuse

USNM 494329, a left maxilla and left dentary from Hole in the Wall, Wyoming; TxVP 46037.1, UWGM 7027 and UWGM 7028, maxillary fragments from Cottonwood Creek, Wyoming[5]

A rhynchosaur, previously assigned to cf. Hyperodapedon sanjuanensis

(in foreground)

Poposaurus gracilis

UR 358, a partial ilium from Lander, Wyoming;[6] UR 357, a partial skeleton including vertebrae, hips, and limb bones[7]

A bipedal poposauroid first described from the Popo Agie Formation and known from more complete specimens from the Chinle Formation[8]

Synapsids

Taxon Member Material Notes Images

Eubrachiosaurus browni

FMNH UC 633, a partial left scapula, left humerus, and left pelvis from Lander, Wyoming

A dicynodont[9]

See also

Footnotes

  1. ^ High, L.R.; Hepp, D.M.; Clark, T.; Picard, M.D. (1969). "Stratigraphy of Popo Agie Formation (Late Triassic), Uinta Mountain Area, Utah and Colorado". Geologic Guidebook of the Uinta Mountains: Utah's Maverick Range (Sixteenth Annual Field Conference ed.). Utah Geological Association. pp. 181–192.
  2. ^ Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607.
  3. ^ a b c Sulej, T. (2002). "Species discrimination of the Late Triassic temnospondyl amphibian Metoposaurus diagnosticus" (PDF). Acta Palaeontologica Polonica. 47 (3): 535–546.
  4. ^ Dawley, R.M.; Zawiskie, J.M.; Cosgriff, J.W. (1979). "A rauisuchid thecodont from the Upper Triassic Popo Agie Formation of Wyoming". Journal of Paleontology. 53 (6): 1428–1431.
  5. ^ Fitch, A. J.; Haas, M.; C’Hair, W.; Ridgley, E.; Ridgley, B.; Oldman, D.; Reynolds, C.; Lovelace, D. M. (2023). "A New Rhynchosaur Taxon from the Popo Agie Formation, WY: Implications for a Northern Pangean Early-Late Triassic (Carnian) Fauna". Diversity. 15 (4): 544. doi:10.3390/d15040544. hdl:10919/114487.
  6. ^ Lees, J.H. (1907). "The skull of Paleorhinus, a Wyoming phytosaur". The Journal of Geology. 15 (2): 121–151. Bibcode:1907JG.....15..121L. doi:10.1086/621382. JSTOR 30056366. S2CID 129850970.
  7. ^ Mehl, M.G. (1915). "Poposaurus gracilis, a new reptile from the Triassic of Wyoming". The Journal of Geology. 23 (6): 516–522. Bibcode:1915JG.....23..516M. doi:10.1086/622268. JSTOR 30067173.
  8. ^ Gauthier, J.A.; Nesbitt, S.J.; Schachner, E.R.; Bever, G.S.; Joyce, W.G. (2011). "The bipedal stem crocodilian Poposaurus gracilis: inferring function in fossils and innovation in archosaur locomotion" (PDF). Bulletin of the Peabody Museum of Natural History. 52 (1): 107–126. doi:10.3374/014.052.0102. S2CID 86687464. Archived from the original (PDF) on 2015-09-24.
  9. ^ Kammerer, C. F.; Fröbisch, J. R.; Angielczyk, K. D. (2013). Farke, Andrew A (ed.). "On the Validity and Phylogenetic Position of Eubrachiosaurus browni, a Kannemeyeriiform Dicynodont (Anomodontia) from Triassic North America". PLOS ONE. 8 (5): e64203. Bibcode:2013PLoSO...864203K. doi:10.1371/journal.pone.0064203. PMC 3669350. PMID 23741307.

References


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