Qingtoushan Formation

Qingtoushan Formation
Stratigraphic range: Middle Permian, Roadian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Underlies	Sunan Formation
Overlies	Yaogou Formation
Thickness	Over 300 metres
Lithology
Primary	Sandstone
Other	Mudstone
Location
Region	Gansu
Country	China
Extent	Qilian Mountains
Type section
Named by	Liu et al
Year defined	2012

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. ^[1] 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. ^[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.

Synapsida

Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Biseridens [3]	B. qilianicus [3]			A well-preserved skull [3]	An anomodont [3]
Sinophoneus [4]	S. yumenensis [4]			A single skull (GMV 1601)	An anteosaurid dinocephalian
Stenocybus [4]	S. acidentatus [4]			A skull (IGCAGS V 361) and fragmentary jaw bones	Jr. synonym of Sinophoneus yumenensis
Raranimus	R. dashankouensis	Dashankou locality		A partial skull	A basal therapsid.

Sauropsida

Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Belebey	B. zhengi				A bolosaurid parareptile
Gansurhinus	G. qingtoushanensis				A captorhinid

Chronisuchia

Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Phratochronis	P. qilianensis				A Chroniosuchid
Ingentidens	I. corridoricus				A Chroniosuchid

Temnospondyli

Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Anakamacops	A. petrolicus				A dissorophid temnospondyl

References

1. Duhamel, A.; Benoit, J.; Rubidge, B. S.; Liu, J. (August 2021). "A re-assessment of the oldest therapsid Raranimus confirms its status as a basal member of the clade and fills Olson's gap" . The Science of Nature. 108 (4): 26. doi:10.1007/s00114-021-01736-y. ISSN   0028-1042. PMID   34115204. S2CID   235403632.
2. 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)
3. Liu, J.; Rubidge, B.; Li, J. (2009). "A new specimen of Biseridens qilianicus indicates its phylogenetic position as the most basal anomodont". Proceedings of the Royal Society B. 277 (1679): 285–292. doi:10.1098/rspb.2009.0883. PMC   2842672 . PMID   19640887.
4. Kammerer, C.F. (2011). "Systematics of the Anteosauria (Therapsida: Dinocephalia)". Journal of Systematic Palaeontology. 9 (2): 261–304. doi:10.1080/14772019.2010.492645. S2CID   84799772.