Popo Agie Formation

Popo Agie Formation
Stratigraphic range: Late Triassic
Type Geological formation
Unit of Chugwater Group
Overlies Gartra Formation
Location
Region North America
Country United States

The Popo Agie Formation is a Triassic geologic formation that outcrops 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

Hyperodapedon cf. H. sanjuanensis

USNM 494329, a left maxilla and premaxilla from Willow Creek, Wyoming[5]

A rhynchosaur

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

One of only two dicynodonts known to have lived in the northern hemisphere during the Late Triassic, the other being Placerias from the Chinle Formation[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. ↑ 3.0 3.1 3.2 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. ↑ Lucas, S.G.; Heckert, A.B.; Hotton, N.III. (2002). "The rhynchosaur Hyperodapedon from the Upper Triassic of Wyoming and its global biochronological significance" (PDF). In Heckert, A.B.; and Lucas, S.G. (eds.). Upper Triassic Stratigraphy and Paleontology 21. New Mexico Museum of Natural History and Science Bulletin. pp. 149–156.
  6. ↑ Lees, J.H. (1907). "The skull of Paleorhinus, a Wyoming phytosaur". The Journal of Geology 15 (2): 121–151. doi:10.1086/621382.
  7. ↑ Mehl, M.G. (1915). "Poposaurus gracilis, a new reptile from the Triassic of Wyoming". The Journal of Geology 23 (6): 516–522. doi:10.1086/622268.
  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.
  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. doi:10.1371/journal.pone.0064203.

References