the Herrerasaurids, which include Staurikosaurus, and the basal sauropodomorph Saturnalia. The contemporaneous occurrence of basal theropods Staurikosaurus, Herrerasaurus, and Eoraptor with the ornithischian Pisanosaurus'' suggests that the main carnivorous and herbivorous lineages were established during the middle part of the Carnian stage. A U-Pb (uranium decay) dating found that the Santa Maria Formation dated around 233.23 million years ago, putting it 1.5 million years older than the Ischigualasto Formation, and making the two formations approximately equal as the earliest dinosaur localities. References External links Dinosaurs of Rio Grande do Sul Prehistoric saurischians Dinosaur genera Late Triassic dinosaurs of South America Triassic Brazil Fossils of Brazil Paleontology in Rio Grande do Sul Fossil taxa described in 1970 Taxa named by Edwin H. Colbert