The vertebrate fauna of the Upper Triassic (Norian: Revueltian) Snyder quarry

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Andrew B. Heckert Ph.D., Professor (Creator)
Appalachian State University (ASU )
Web Site:

Abstract: Since the first scientific excavations, it has been apparent that the Snyder quarry represents a unique vertebrate fossil assemblage. This assemblage includes an apparent xenacanthid shark, semionotid and redfieldiid fish, a metoposaurid amphibian, a probable procolophonid reptile, a cynodont, an apparent lepidosauromorph, abundant specimens of the phytosaur Pseudopalatus, the aetosaurs Typothorax coccinarum Cope and Desmatosuchus chamaensis Zeigler, Heckert and Lucas, the rauisuchian Postosuchus (sensu stricto), a sphenosuchian and theropod dinosaurs referable to Eucoelophysis. Archosaurs dominate the assemblage, and the phytosaurs, and aetosaurs are all treated separately elsewhere in this volume. The xenacanth apparently pertains to the “Xenacanthus” moorei group and, if it is not a contaminant from screenwashing processes, is one of the youngest xenacanth sharks known. Most osteichthyan fossils at the Snyder quarry are isolated scales and bones, though an incomplete, articulated semionotid has been recovered. The sole metoposaurid fossils recovered to date are a fragmentary, large centrum and isolated teeth that probably pertain to Buettneria and would thus be one of the youngest Buettneria records known. The possible procolophonid fossil consists of a single tooth and remains problematic. The cynodont is represented by an incomplete left distal humerus. The lepidosauromorph is based on an incomplete jaw fragment bearing many pleurodont teeth. The archosaur fauna is somewhat typical of Revueltian Chinle faunas in that it includes the phytosaur Pseudopalatus and the aetosaur Typothorax coccinarum, both index taxa of the Revueltian (early-mid Norian) land-vertebrate faunachron. Rarer archosaurian taxa include the aetosaur Desmatosuchus chamaensis, the theropod dinosaurs, the rauisuchian Postosuchus and the indeterminant sphenosuchian. The rauisuchian is represented by fragmentary postcrania that, from their disparate sizes, clearly represent at least two different individuals.

Additional Information

Zeigler, K.E., Heckert, A.B., and Lucas, S.G., (2003) The vertebrate fauna of the Upper Triassic (Norian: Revueltian) Snyder quarry: New Mexico Museum of Natural History and Science Bulletin 24 (Paleontology and Geology of the Upper Triassic (Revueltian) Snyder Quarry, New Mexico) , p. 71-79. (ISSN 1524-4156) Archived in NC DOCKS with permission of the editor. The version of record is available at:
Language: English
Date: 2003

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