A new herrerasaurid (Dinosauria, Saurischia) from the Upper Triassic Ischigualasto Formation of northwestern Argentina

A new herrerasaurid dinosaur, Sanjuansaurus gordilloi, has been identified from the Upper Triassic Ischigualasto Formation in northwestern Argentina. This discovery challenges previous assumptions about the diversification of saurischian dinosaurs, suggesting that they were already widely diversified by the late Carnian period rather than increasing in diversity across the Carnian-Norian boundary. The research involved a phylogenetic analysis that placed Sanjuansaurus within Herrerasauridae, at the base of Theropoda, alongside other known taxa such as Herrerasaurus and Staurikosaurus. The study highlights the significant paleontological importance of the Ischigualasto/Talampaya Natural Parks, contributing to our understanding of early dinosaur evolution in southwestern Pangea.

Martínez, R., & Alcober, O. (2010). A new herrerasaurid (Dinosauria, Saurischia) from the Upper Triassic Ischigualasto Formation of northwestern Argentina. ZooKeys, 63, 55–81. https://doi.org/10.3897/zookeys.63.550