Coelophysis bauri Cope 1887

Coelophysis bauri (Cope, 1887); metataxon

Age. Norian.

Occurrence. Chinle Formation, Arizona, New Mexico;?Dockum Group, exas, USA.

Diagnosis. Coelophysis differs from Eoraptor, Herrerasaurus and Staurikosaurus in the presence of pleurocoels in the dorsal vertebrae, the more elongated dorsal vertebrae, five fused sacral vertebrae, dolichoiliacic ilium, presence of a small lateral projection on the distal end of the tibia and the functionally tridactyl foot with a Mt I that is attached to Mt II and does not reach the ankle joint. It differs from Gojirasaurus in the relatively lower dorsal neural spines and the significantly smaller size, from Liliensternus in the absence of a broad ridge that extends from the posterior end of the diapophyses to the posterior end of the vertebral centra in cervical vertebrae and the smaller size, from Procompsognathus in the considerably larger overall size, from Shuvosaurus in the lack of any of the derived cranial features of the latter taxon, and from the slightly younger, but very similar Syntarsus in the lack of a postnasal fenestra.

Remarks. In agreement with Colbert et al. (1992), the name Coelophysis bauri is used here for the common small theropod dinosaur of the Ghost Ranch locality in New Mexico. A problem with the Ghost Ranch material is the variation between individuals. Colbert (1989, 1990) noted many differences between several individuals of Coelophysis from this locality and explained them as either ontogenetic differences or sexual dimorphism. Other workers believe that there is more than one species of theropod represented in the material from this locality (Cuny, pers. comm. 1998). Although my own observations of specimens and close inspections of published photographs revealed several differences between different specimens from this locality, these differences seem to be too insignificant to indicate different taxa. Pending a detailed revision of the Ghost Ranch material, it is assumed here that all the material represents a single species, Coelophysis bauri (Text-fig. 4f).