Pampadromaeus (Greek for "Pampas runner"); pronounced pam-pah-DRO-may-us
Woodlands of South America
Middle Triassic (230 million years ago)
Size and Weight:
About 5 feet long and 100 pounds
Small size; long hind legs
About 230 million years ago, during the middle Triassic period, the first true dinosaurs evolved in what is now modern-day South America. In the beginning, these small, nimble creatures consisted of basal theropods like Eoraptor and Herrerasaurus, but then an evolutionary shift occurred that gave rise to the first omnivorous and herbivorous dinosaurs, which themselves evolved into the very first prosauropods like Plateosaurus.
That's where Pampadromaeus comes in: this newly discovered dinosaur seems to have been intermediate between the very first theropods and the first true prosauropods. Oddly enough for what paleontologists call a "sauropodomorph" dinosaur, Pampadromaeus possessed a very theropod-like body plan, with long hind legs and a narrow snout. The two types of teeth embedded in its jaws, leaf-shaped ones in front and curved ones in back, indicate that Pampadromaeus was a true omnivore, and not yet a devoted plant-muncher like its more famous descendants.