The Popo Agie Formation ( )Locally "po-PO-zha" according to Don Pitcher, 2006, Moon Handbooks Wyoming, p. 269 More ambiguous transcription of "po-po-zsha" at 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. The earliest known dinosaur of the Laurasian continent, Ahvaytum, is discovered from the Popo Agie Formation. Dinosaurian trace fossils and fragmentary fossils of prehistoric reptiles and amphibians, including pseudosuchian reptiles and temnospondyl amphibians, have also been reported from this formation.

Paleobiota

Amphibians

Taxon Species Member Material Notes Images Apachesaurus A. sp. Complete skull A metoposaurid temnospondyl, originally described as Anaschisma sp. and later Eupelor browni Anaschisma A. browni Complete skull A metoposaurid temnospondyl Metoposauridae Indeterminate Complete skull Originally described as Anaschisma browni

Reptiles

Taxon Species Member Material Notes Images Ahvaytum A. bahndooiveche UWGM 1975, a left astragalus, and UWGM 7549, a partial left femur A probable sauropodomorph dinosaur and the oldest known Laurasian dinosaur Heptasuchus H. clarki UW 11562, a partial skull and postcranial skeleton; UW 11563 through UW 11565, partial postcranial remains; both from Big Horn Mountains, Wyoming A rauisuchian (in background) Beesiiwo B. 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 A rhynchosaur, previously assigned to cf. Hyperodapedon sanjuanensis (in foreground) Poposaurus P. gracilis UR 358, a partial ilium from Lander, Wyoming; UR 357, a partial skeleton including vertebrae, hips, and limb bones A bipedal poposauroid first described from the Popo Agie Formation and known from more complete specimens from the Chinle Formation Sulcimentisauria indet. Indeterminate A partial left humerus and right femur A 'silesaurid'

Synapsids

Taxon Species Member Material Notes Images Eubrachiosaurus E. browni FMNH UC 633, a partial left scapula, left humerus, and left pelvis from Lander, Wyoming A dicynodont

See also

List of dinosaur-bearing rock formations List of stratigraphic units with indeterminate dinosaur fossils

Footnotes

References Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. .