New Mexico Geological Society Annual Spring Meeting — Abstracts

Late Triassic omithischian dinosaurs are uncommon in North America. The largest and best known is Revueltosaurus callenderi. Revueltosaurus was named for numerous teeth from the Revueltian Bull Canyon Formation of east-central New Mexico. These teeth represent all portions of the dentition and include unusual incisor-like teeth that suggest a dentulous anterior to the dentary and hence the absence of a pre-dentary. Revueltosaurus only occurs in the lower portion of the Bull Canyon Formation in paleosol-hosted taphofacies. The associated fauna includes a variety of theropod dinosaurs, advanced crurotarsans such as sphenosuchians, a diverse assemblage of small, enigmatic reptiles including a Vancleavia-like form and the metoposaurid amphibian Apachesaurus.

Revueltosaurus callenderi is also now known from numerous specimens from Petrified Forest National Park. These specimens derive from the lower portion of the Revueltian Painted Desert Member of the Petrified Forest Fonnation. As in New Mexico, Revueltosaurus is restricted to paleosol-hosted taphofacies and the associated fauna is very similar, but not quite as diverse. Taxa held in common between Revueltosaurus-bearing localities in New Mexico and Arizona include theropods (Coelophysis, Chindesaurus), an undescribed armored crurotarsan, Hesperosuchus, the Vancleavia-like form and Apachesaurus.

It is clear that Revueltosaurus is restricted to the older portion of the Revueltian land vertebrate faunachron and can be considered an index fossil of this time interval. The taphonomic setting and associated fauna indicate that Revueltosaurus, like contemporary theropod dinosaurs, was restricted to drier environments than the contemporaneous semi-aquatic community that is dominated by phytosaurs.