A new specimen of the early branching crocodyliform Platyognathus hsui extends the record of gobiosuchids back 67 million years

Abstract

Crocodyliforms are poorly known from the Early Jurassic Lufeng Formation of China, and a new specimen of Platyognathus hsui is by far the most complete specimen yet known. It shares with the missing holotype and the neotype the very unusual features of a dentary caniniform that is polygonal in cross-section and the complete fusion of the dentary symphysis, and the new specimen provides four additional features diagnosing the species. Features such as a relatively broad rostrum and a posteroventrolateral process on the squamosal place it with taxa closer to extant crocodylians than are Orthosuchus and Protosuchus, as an early branching relative of the Gobiosuchidae. The oldest previous record of the gobiosuchid lineage was from the late Barremian stage of the Early Cretaceous, and this extends the fossil record of the lineage back by 67 Myr. We recognize a new superfamily, Gobiosuchoidea, to include Platyognathus hsui and gobiosuchids.