Eodromaeus (Greek for "dawn runner"); pronounced EE-oh-DRO-may-us
Woodlands of South America
Middle Triassic (230 million years ago)
Size and Weight:
About 4 feet long and 10-15 pounds
Small size; bipedal posture
As far as paleontologists can tell, it was in middle Triassic South America that the most advanced archosaurs evolved into the very first dinosaurs--small, skittery, bipedal meat eaters that were destined to split off into the more familiar saurischian and ornithischian dinosaurs of the Jurassic and Cretaceous periods. Announced to the world in January of 2011, by a team including the ubiquitous Paul Sereno, Eodromaeus was very similar in appearance and behavior to other "basal" South American dinosaurs like Eoraptor and Herrerasaurus. This small theropod's near-complete skeleton was cobbled together from two specimens found in Argentina's Valle de la Luna, a rich source of Triassic fossils.