One of the earliest theropods, Coelophysis was a small and nimble, birdlike carnivore that darted after prey in the riverside forests of the Triassic Period, snapping up small lizards. It was built for speed, with lightweight, hollow bones and a slender frame. In 1998 a Coelophysis skull was taken on board space shuttle Endeavour, making it the second dinosaur (after Maiasaura) to visit space.
Coelophysis had hundreds of small, sharp teeth. They had sawtooth edges—a sign that it ate flesh. Coelophysis had a long, flexible neck that formed an S-shape when relaxed, like the neck of a heron.
By straightening its neck quickly, it could dart for fast-moving prey on the ground. The tail was long and stiff. It acted like a rudder, helping Coelophysis balance when running after prey or fleeing from bigger carnivores.
■ When: 215 million years ago (Late Triassic)
■ Fossil location: N. America, southern Africa, China
■ Habitat: Desert plains
■ Length: 10 ft (3 m)
■ Diet: Lizards and fish
Coelophysis was as long as a small car but as light as an 8-year-old child. With a long, curved neck and slender legs, it resembled a long-legged bird. In 1947 scientists made an amazing discovery of 500 Coelophysis skeletons piled together at Ghost Ranch in New Mexico—a Coelophysis “graveyard.” They seem to have died together, perhaps victims of a sudden flood. The find inspired stories of Coelophysis hunting in huge packs to overpower large prey, but there is no evidence this happened.
Tiny bones in the stomach of this fossilized Coelophysis were once thought to be those of a baby Coelophysis and a sign of cannibalism. However, some experts now think the bones were those of other reptiles that Coelophysis hunted.