ANATOMY AND PHYLOGENETIC-RELATIONSHIPS OF CHIMAERASUCHUS-PARADOXUS, AN UNUSUAL CROCODYLIFORM REPTILE FROM THE LOWER CRETACEOUS OF HUBEI, CHINA

The crocodyliform reptile Chimaerasuchus paradoxus Wu, Sues, and Sun, 1995 from the Lower Cretaceous Wulong Formation of Hubei (China) is ch aracterized by its singular, extremely heterodont dentition. It also p ossesses a number of unusual cranial features including a shelf-like a nterolateral expansion of the jugal, a distinct lateral process on the angular, a very small splenial, and an entirely open Meckelian canal. As in Notosuchus terrestris from the Upper Cretaceous of Argentina, t he confluent external nares are large, vertically oriented, and face d irectly forward. Mandibular motion was apparently proal. Phylogenetic analysis indicates a sister-group relationship between Chimaerasuchus and Notosuchus, and between that clade and an as yet unnamed notosuchi d from the Lower Cretaceous of Malawi. This casts further doubts on pr evious claims concerning the endemic distribution of the Notosuchidae and other ''Gondwanan'' tetrapod taxa during the Cretaceous.