Zupaysaurus

Phylogeny: Dinosauria > Saurischia > Theropoda > Neotheropoda

Overview: Growing to be only four to five meters long with a slender build, Zupaysaurus wasn’t a very large theropod in the grand scheme of things. However, for the Late Triassic, it was decently large. Its earliest dinosaurian ancestors were considerably smaller. Still, despite its impressive size for that point in time, Zupaysaurus still may’ve lived in the shadow of much larger, non-dinosaurian predators. This likely included land-dwelling, distant crocodile relatives like Fasolasuchus, isolated bones of which suggest lengths of up to nine or ten meters, which was much larger than any known theropod both at that time and a fair ways into the Jurassic Period. Even so, Zupaysaurus would’ve been a force to be reckoned with as far as the young of dinosaurs like Lessemsaurus or Riojasaurus were concerned. Fossils of these animals are all known from Argentina’s Los Colorados Formation.

Zupaysaurus was first described in 2003, based on most of its skull, parts of the shoulder, vertebrae, and a few limb bones. Its generic name means “devil lizard”, though it more specifically refers to an entity from Incan mythology called “Supay” or “Zupay”, a deity linked with death and the underworld. To this day, Zupaysaurus is only known from one fossil specimen, the holotype, originally discovered six or so years prior to its description. Based on the known material, we can see that Zupaysaurus sported a slender-snouted, lightly constructed skull that probably had a pair of low crests running down the length of the snout. There was a notable notch near the tip of its upper jaw, which we often see on the snouts of basal neotheropods. Some classify it close to Coelophysis and its family, but others see it as a more generalized neotheropod, probably more basal than Dilophosaurus or Cryolophosaurus.