17 - Buriolestes schultzi (from Greek "Buriol's robber")
18 - Staurikosaurus pricei (from Greek "Southern Cross lizard")
- Late Triassic (233 Ma BCE)
- Santa Maria Formation, Rio Grande do Sul
One of the great discoveries of 2016, the Buriolestes is a sauropodomorph, the lineage of non-avian dinosaurs characterized by their relatively rounded bodies, front legs with clawed first fingers and relatively long tails and necks, which over millions of years would be slowly replaced by the immense sauropods as the main herbivores in various environments around the world. However, unlike the most famous Plateosaurus and Musaurus, Buriolestes had sharp, serrated teeth, better adapted to a carnivorous and possibly omnivorous diet, unlike the leaf-shaped teeth of their herbivorous relatives. Such a characteristic would indicate that, initially on their evolutionary path, the Saurischians and probably the dinosaurs as a whole were all carnivores, gradually replacing the other animals that dominated several niches until the End-Triassic mass extinction circa 201 Ma BCE, after which the dinosaurs became the lords of the world.
Amidst the sparse dry forests cut by rivers of the Santa Maria Formation, the Buriolestes would probably come into direct confrontation with the Staurikosaurus, a medium-sized herrerasauridae, about 2 meters long and 80 kg, being the first dinosaur described in Brazilian territory by American Edwin Harris Colbert, at the service of the American Museum of Natural History, where the fossil remains to this day. Competing with its most massive relative, the Gnathovorax, and the immense rauisuchian Prestosuchus, Staurikosaurus, like other herrerasauridae, was an active and opportunistic predator, feeding mainly on small animals, such as rhynchosaurs, lagerpetids and proto-mammals. The relationship between herrerasauridae and other dinosaurs is still nebulous, classically considered as distant cousins of the theropods or, in a more recent classification, as a sister group of sauropodomorphs within Saurischia, with theropods and ornithischians together in a separate group, called Ornithoscelida (Baron et al, 2017).
