Popo Agie Formation
Geologic formation in the United States
From Wikipedia, the free encyclopedia
The Popo Agie Formation (/poʊˈpoʊʒə/ poh-POH-zhə)[1][2] 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.[3] 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.[4]
| Popo Agie Formation | |
|---|---|
| Stratigraphic range: Late Triassic | |
| Type | Geological formation |
| Unit of | Chugwater Group |
| Overlies | Gartra Formation |
| Location | |
| Region | North America |
| Country | United States |
Paleobiota
Color key
|
Notes Uncertain or tentative taxa are in small text; |
Amphibians
| Taxon | Species | Member | Material | Notes | Images |
|---|---|---|---|---|---|
| Apachesaurus | A. sp. | Complete skull | A metoposaurid temnospondyl, originally described as Anaschisma sp. and later Eupelor browni[5] |  | |
| Anaschisma | A. browni | Complete skull | A metoposaurid temnospondyl[6] |  | |
| Metoposauridae | Indeterminate | Complete skull | Originally described as Anaschisma browni[5] | ||
Reptiles
| Taxon | Species | Member | Material | Notes | Images |
|---|---|---|---|---|---|
| Ahvaytum[4] | 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[7] | A rauisuchian | 
| |
| 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[8] | A rhynchosaur, previously assigned to cf. Hyperodapedon sanjuanensis |
| |
| Poposaurus | P. gracilis | UR 358, a partial ilium from Lander, Wyoming;[9] UR 357, a partial skeleton including vertebrae, hips, and limb bones[10] | A bipedal poposauroid first described from the Popo Agie Formation and known from more complete specimens from the Chinle Formation[11] | .jpg) | |
| Sulcimentisauria indet.[4] | 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[12] |  | |
