A Norian Lagerpetid Dinosauromorph from the Quebrada Del Barro Formation, Northwestern Argentina

Abstract. The early evolution of Ornithodira —the clade including pterosaurs and dinosaurs— is poorly known. Until a decade ago, the basal radiation of Dinosauromorpha, the clade including dinosaurs and birds, was poorly understood because of the poor fossil record restricted to specimens known from the Ladinian Chanares Formation in Argentina. Over the last years the discovery of several non-dinosaurian dinosauromorphs dramatically expanded this record and also demonstrated that this group —previously restricted to de Middle Triassic— survived at least well into the Norian. Although Norian non-dinosaurian dinosauromorphs have been reported from several regions around the world, the only known Norian non-dinosauriform dinosauromorphs —Dromomeron romeri Irmis, Nesbitt, Padian, Smith, Turner, Woody, and Downs and Dromomeron gregorii Nesbitt, Irmis, Parker, Smith, Turner, and Rowe— come from North America. We report here the first record from the Southern Hemisphere of a non-dinosauriform dinosauromorph, Dro...