Anatomy

Dilophosaurus Dilophosaurus was a speedy, slender, bipedal (walked on two legs), meat-eater that lived during the early Jurassic period. It was a theropod (a meat-eating dinosaur) about 20 feet (6 m) long, about 5 feet (1.5 m) tall at the hip, and weighing about 650 to 1,000 pounds (300 kg to 450 kg).

An example of a dewclaw

Dilophosaurus had a dewclaw.

It 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.

Dilophosaurus labeled diagram

When Dilophosaurus Lived

Dilophosaurus lived about 201 to 189 million years ago, during the early Jurassic period.

Among its contemporaries in North America during this time, all smaller than Dilophosaurus, were:

  • the meat-eaters Coelophysis (about 10 feet long), Syntarsus, and Segisaurus
  • the omnivores Massopondylus and Anchisaurus
  • the plant-eaters Scutellosaurus and Ammosaurus.

Behavior

Dilophosaurus may have roved in packs, since three specimens were found together in Arizona, USA.

Diet

Dilophosaurus was a carnivore, a meat eater. It had loosely attached jaws which would have made killing animals with its teeth difficult. It must have killed with its clawed arms and legs, and/or scavenged carcasses.

Locomotion

Dilophosaurus walked on two muscular legs and was a relatively fast runner, leaving bird-like footprints on land. Some of its fossilized footprints are only impressions of the claw-tips. This indicates that Dilophosaurus may have been walking in water at the time. Dilophosaurus’ leg length was about 1.65 m; it’s stride length (distance between footprints) was about 2.13 m.

Discover of Fossils

Map of Dilophosaurus fossils The first fossil Dilophosaurus skeleton was found in Arizona, USA, in the 1940’s. Dilophosaurus was named in 1970 by Samuel P. Welles. There have been three Dilophosaurus fossils found in the USA, all found together in Arizona. They are now at the University of California’s Museum of Paleontology at Berkeley, USA. Another specimen may have been found in China.

Classification

Dilophosaurus belonged to the:

  • Kingdom Animalia (animals)
  • Phylum Chordata (having a hollow nerve chord ending in a brain)
  • Class Archosauria (diapsids with socket-set teeth, etc.)
  • Order Saurischia - lizard-hipped dinosaurs
  • Suborder Theropoda - bipedal carnivores
  • Family Ceratosauria (also called Coelophysoidea - the most primitive theropod group, which includes Dilophosaurus and Segisaurus)
  • Genus Dilophosaurus
  • Species
    • D. wetherilli is the type species (named by Welles in 1954, but it was originally called Megalosaurus).