Eoraptor is one of the earliest known dinosaurs. This primitive theropod (meat-eating dinosaur) lived during the late Triassic about 228 million years ago.
Anatomy: Eoraptor was a small, lightly-built dinosaur that walked on two long legs. It was about 3 feet long (1 m); it had light, hollow bones, a long head with dozens of small, sharp teeth, and five fingers on its hands (two of the fingers on each hand were very small).
Fossils and Name: Eoraptor means "dawn thief." Eoraptor was first found by Ricardo Martinez in 1991 in Argentina, South America, in the Ischigualasto Basin. This area was a river valley during the late Triassic period but is a dry, eroding desert badlands today. Eoraptor was named by paleontologists P. Sereno, Forster, Rogers, and Monetta in 1993.