Revision of Platypterygius hauthali von Huene, 1927 (Ichthyosauria: Ophthalomosauridae) from the early cretaceous of Patagonia, Argentina

Abstract

Most of the Cretaceous ichthyosaurian materials are referable to the single genus Platypterygius, which includes seven species. Although Cretaceous ichthyosaurs were probably cosmopolitan in their distribution, South American records are scarce. In recent revisions, the name Platypterygius hauthali has been retained for Early Cretaceous material from South America, but no specific diagnosis has been provided. The species P. hauthali was proposed on the basis of fragmentary material from the Neocomian of Santa Cruz Province (Patagonia, Argentina). However, analysis of the forefin features of the holotype shows that the pattern of carpal ossifications is different from that of other species of the genus and, furthermore, that this pattern is sufficient for specific diagnosis. Based on these data and additional findings of ichthyosaurs in Neuquén, Argentina, it can be concluded that there are three valid ichthyosaur taxa present in the Early Cretaceous of South America: Caypullisaurus bonapartei (Berriasian of Neuquén, Argentina), Platypterygius hauthali (Early Barremian of Santa Cruz, Argentina) and P. sachicarum (Barrenian-Aptian of Colombia).