An Ictidosaur Fossil from North America

Science  10 Jun 1983:
Vol. 220, Issue 4602, pp. 1151-1153
DOI: 10.1126/science.220.4602.1151


Teeth of a North American ictidosaur, Pachygenelus milleri, n. sp., found in the Upper Triassic Dockum Group of Texas, indicate that it is very similar to Pachygenelus monus of South Africa and Chaliminia musteloides of South America. The presence of a Gondwana element in the Northern Hemisphere attests to the ease of dispersal of the Late Triassic vertebrates through Pangea. Ictidosaurs are small, highly advanced, carnivorous cynodonts that display a mosaic of reptilian and mammalian features in the masticatory apparatus. They were contemporaneous with early mammals and probably closely related to them.