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Post Quarry Triassic vertebrates from Texas



From: Ben Creisler
bcreisler@gmail.com


A new online paper:

Jeffrey W. Martz, Bill Mueller, Sterling J. Nesbitt, Michelle R.
Stocker, William G. Parker, Momchil Atanassov, Nicholas Fraser,
Jonathan Weinbaum and James R. Lehane (2013)
A taxonomic and biostratigraphic re-evaluation of the Post Quarry
vertebrate assemblage from the Cooper Canyon Formation (Dockum Group,
Upper Triassic) of southern Garza County, western Texas.
Earth and Environmental Science Transactions of the Royal Society of
Edinburgh (advance online publication)
DOI: http://dx.doi.org/10.1017/S1755691013000376
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9015654&fulltextType=RA&fileId=S1755691013000376

The Post Quarry, within the lower part of the type section of the
Upper Triassic Cooper Canyon Formation in southern Garza County,
western Texas, contains a remarkably diverse vertebrate assemblage.
The Post Quarry has produced: the small temnospondyl Rileymillerus
cosgriffi; the metoposaurid Apachesaurus gregorii; possible
dicynodonts and eucynodonts; a clevosaurid sphenodontian;
non-archosauriform archosauromorphs (Trilophosaurus dornorum,
simiosaurians, and possibly Malerisaurus); the phytosaur Leptosuchus;
several aetosaurs (Calyptosuchus wellesi, Typothorax coccinarum,
Paratypothorax, and Desmatosuchus smalli); the poposauroid Shuvosaurus
inexpectatus (“Chatterjeea elegans”); the rauisuchid Postosuchus
kirkpatricki; an early crocodylomorph; several dinosauromorphs (the
lagerpetid Dromomeron gregorii, the silesaurid Technosaurus smalli, a
herrerasaurid, and an early neotheropod); and several enigmatic small
diapsids. Revised lithostratigraphic correlations of the lower Cooper
Canyon Formation with the Tecovas Formation, the occurrence of
Leptosuchus, and the overall composition of the assemblage indicate
that the Post Quarry falls within the Adamanian biozone, and not the
Revueltian biozone. Stratigraphic subdivision of the Adamanian biozone
may be possible, and the Post Quarry may be correlative with the upper
part of the Adamanian biozone in Arizona. The age of the Post Quarry
assemblage is possibly late Lacian or earliest Alaunian (late early
Norian or earliest middle Norian), between 220 and 215 Ma.