Tetrapod footprint ichnofauna of the Upper Triassic Redonda Formation, Chinle Group, Quay County, New Mexico
— Spencer G. Lucas, Adrian P. Hunt, and Martin G. Lockley
The tetrapod footprint ichnofauna from the Upper Triassic Redonda Formation in Quay County, east-central New Mexico, consists of four ichnogenera—Rhynchosouroides (rhynchocephalian), Brachychirotherium (aetosaur), Grallator (theropod) and Pseudotetrasauropus (prosauropod). A unique feature of the Redonda tetrapod ichnofauna is the absence of the sauropod track Tetrasauropus and the dominance of the prosauropod track Pseudotetrasauropus, which may indicate a local, mutual ecological separation of prosauropods and sauropods. This dominance of prosauropod tracks in the Redonda Formation is not mirrored by its body fossil record, which lacks prosauropods and is dominated by semiaquatic taxa. The Redonda tetrapod ichnofauna resembles other Chinle Group tetrapod ichnofaunas of the Apachean Rock Point sequence and well represents a global Late Triassic ichnofauna characterized by Rhynchosauroides, Brachychirotherium, Grallator, Pseudotetrasauropus and Tetrasauropus.
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- Lucas, Spencer G.; Hunt, Adrian P.; Lockley, Martin G., 2001, Tetrapod footprint ichnofauna of the Upper Triassic Redonda Formation, Chinle Group, Quay County, New Mexico, in: Geology of the Llano Estacado, Lucas, Spencer G.; Ulmer-Scholle, Dana S., New Mexico Geological Society, Guidebook, 52nd Field Conference, pp. 177-180.