Coelophysis (meaning "Hollow Form") was one of the earliest dinosaurs. It was a small, carnivorous biped that lived in North America during the Late Triassic Period. Although Coelophysis was once thought to be a cannibal, recent studies have shown that what was once thought to be an adult with a juvenile in its stomach was in fact two separate skeletons which had died on top of each other. In the first episode of Walking with Dinosaurs, it is shown hunting lung fish, Cynodonts and eating a dying Postosuchus and younger members during a drought.
Coelophysis was also one of the earliest Ceratosaurs, a group that would go on to diversify into genuses such as Megapnosaurus, Dilophosaurus, Liliensternus, and Ceratosaurus, as well as the more advanced Abelisaurs.