The Qingtoushan Formation is a Middle Permian-age geologic formation in the Qilian Mountains of Gansu, China. It is known for its diverse tetrapod fauna known as the Dashankou fauna, which likely dates to the Roadian, and includes some of the oldest known therapsids. This formation was previously erroneously named as the Xidagou Formation, a name which applies to otherwise Triassic strata in the northern Qillian Mountains. The formation is over 300 metres thick, and primarily consists of purple-red coarse sandstones, with minor purple mudstone.Liu J, Qinghua S, Keqin S, Lu L (2012) The horizon of Dashankou Fauna and the Permo-Triassic strata in northern Qilian area, China. Vertebr Palasiat 50(4):373–381 (In Chinese)
Paleobiota
Synapsida Genus Species Location Stratigraphic position Material Notes ImagesBiseridensB. qilianicusA well-preserved skull An anomodontSinophoneusS. yumenensisA single skull (GMV 1601) An anteosaurid dinocephalianStenocybusS. acidentatusA skull (IGCAGS V 361) and fragmentary jaw bonesJr. synonym of Sinophoneus yumenensisRaranimusR. dashankouensisDashankou localityA partial skull A basal therapsid
Other Tetrapoda Genus Species Location Stratigraphic position Material Notes ImagesAnakamacopsA. petrolicusA dissorophid temnospondylBelebeyB. zhengiA bolosaurid stem-reptileGansurhinusG. qingtoushanensisA captorhinidIngentidensI. corridoricusA chroniosuchid chroniosuchianPhratochronisP. qilianensisA chroniosuchid chroniosuchianYumenerpetonY. yangiA bystrowianid chroniosuchian
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