Dilophosaurus was a small, primitive, meat-eating dinosaur with two thin, hollow, bony crests on its head. This theropod lived during the early Jurassic period roughly 201 to 189 million years ago. Dilophosaurus was a speedy, lightly-built, bipedal (walked on two legs), meat-eating dinosaur. Dilophosaurus may have roved in packs, since three specimens were found together in Arizona, USA.
Anatomy: Dilophosaurus had two thin, bony, almost semi-circular crests on its head; these may have been for mating displays. It had short arms with three-fingered hands and strong legs with four-toed feet (one toe was a dewclaw ). Both fingers and toes had claws. It had hollow bones and an S-shaped, curved neck. It had loosely attached jaws which would have made killing animals with its teeth difficult.
Fossils and Name: The first fossil Dilophosaurus skeleton was found in Arizona, USA, in the 1940's. Dilophosaurus was named in 1970 by Samuel P. Welles. Fossils have been found in the USA and China.