Marasuchus

Marasuchus (meaning "Mara crocodile") is an early genus of dinosauriform archosaur, one of the closest relatives of dinosaurs. It is sometimes regarded as a junior synonym of Lagosuchus (which would make Marasuchus an invalid later name for Lagosuchus fossils). Both names have been applied to small bipedal dinosauriform fossils from the same time and place: the Late Triassic (early Carnian stage) of what is now La Rioja Province, Argentina. If valid, Marasuchus contains a single species, Marasuchus lilloensis.

Marasuchus lilloensis was originally designated as Lagosuchus lilloensis in 1972. It was named for a few well-preserved dinosauriform fossils stored at PVL, a museum in San Miguel de Tucuman. L. lilloensis is the second named species of Lagosuchus, a contemporary archosaur described from a smaller and more fragmentary fossil the previous year. A 1994 study argued that the first species, Lagosuchus talampayensis, has insufficient fossil material to justify its continued use. In response, the same study gave the better-preserved PVL fossils a new genus: Marasuchus.