Article: A staurikosaurid dinosaur from the Upper Triassic Ischigualasto Formation of Argentina and the relationships of the Staurikosauridae

A partial skeleton of a staurikosaurid, cf. Staurikosaurus sp. is described from the Ischigualasto Formation of Argentina. This specimen provides additional anatomical data for an evaluation of the phylogenetic affinities of the Staurikosauridae. Colbert's (1970) assignment of Staurikosaurus to the Dinosauria is supported. No synapomorphies exist to support close relationships between Herrerasaurus and Staurikosaurus. It is concluded that Staurikosaurus and Herrerasaurus form successive sister taxa to an assemblage composed of Ornithischia and Saurischia, with the latter only including Sauropodomorpha and Theropoda.