A bizarre predatory dinosaur from the Late Cretaceous of Madagascar

Here we report the discovery of a small-bodied (similar to1.8 m) predatory dinosaur from the Late Cretaceous (Maastrichtian) of Madagascar. Masiakasau rus knopfleri, gen. et sp. nov., represented by several skull elements and much of the postcranial skeleton, is unique in being the only known theropo d with a highly procumbent and distinctly heterodont lower dentition. Such a derived dental morphology is otherwise unknown among dinosaurs. Numerous skeletal characteristics indicate that Masiakasaurus is a member of Abelisa uroidea, an enigmatic clade of Gondwanan theropods. Previously, small-bodie d abelisauroids were known only from Argentina(1-3). The occurrence of Masi akasaurus on Madagascar suggests that small-bodied abelisauroids, like thei r larger-bodied counterparts, were more cosmopolitan, radiating throughout much of Gondwana and paralleling the diversification of small coelurosaur t heropods in Laurasia.