 The first aetosaurs from North America were also being described at this time. American paleontologist Edward Drinker Cope named Typothorax in 1875 and Episcoposaurus in 1877, both of which were from New Mexico. However, Cope considered these genera to be phytosaurs, crocodile-like aquatic archosaurs that were also common in the Late Triassic. While new material referable to Typothorax has been found in recent years throughout the American southwest, Episcoposaurus is no longer considered valid. Cope, along with later paleontologists such as Friedrich von Huene, recognized that remains of the type species E. horridus actually belonged to Typothorax. Another species, E. haplocerus, was reassigned to Desmatosuchus in 1953.
