Coelophysis (“hollow form”) appeared around 215 million years ago. It was a small, relatively delicate dinosaur, measuring up to 10 feet (3 meters) in length, with an elongated neck, strong grasping hands, and a long, slender skull with sharp teeth. As it walked on two legs, Coelophysis used its long, slender tail for balance. Its feet were narrow, with only three prominent toes, a distinctive characteristic of the theropods. The Coelophysis were part of a carnivorous dinosaur group that later included the Tyrannosaurus rex and Velociraptor.