Dilophosaurus

Phylogeny: Dinosauria > Saurischia > Theropoda > Neotheropoda > Dilophosauridae

Overview: Dilophosaurus fossils were first discovered in the early 1940’s, on what is today Navajo land in the state of Arizona. They consisted of a few partial skeletons, which were first described in 1954 by paleontologist Samuel P. Welles. Welles would refer these specimens to the famous genus Megalosaurus, as a new species. More complete fossils would come to light in the 1960’s, some of which included the remnants of prominent head crests which revealed to Welles the actual truth – it was its own, separate genus. Welles formally established Dilophosaurus as such in 1970. The genus takes its name from Greek root words, together meaning “two-crested lizard”, inspired by the paired crests that ran along the length of its snout and over the eyes. All confirmed fossils of this dinosaur come from the Kayenta Formation, dated to the Early Jurassic. Some remains found in China were once referred to Dilophosaurus as an additional species, but they have since been re-classified as belonging to a separate genus called Sinosaurus. Dilophosaurus may’ve coexisted with the basal sauropodomorph Sarahsaurus and the small armored dinosaur Scutellosaurus, both of which were potential prey.

Contrary to some famous film portrayals, Dilophosaurus wasn’t a small theropod. Indeed, growing to be six or seven meters long, it was actually one of the largest land predators of the Early Jurassic, rivaled only by dinosaurs like Cryolophosaurus. Both animals, however, were lightly built, as was typical for such early theropods. Dilophosaurus was at first classified as a megalosauroid and later as a relative of either Coelophysis or Ceratosaurus. Currently, paleontologists treat it as a basal member of the clade Neotheropoda. It was “primitive”, but more derived than Coelophysis and its family. Dilophosaurus may belong to its own family, the Dilophosauridae, but there is some debate over what if any other dinosaurs really belonged to the clade. There is also no fossil evidence of either venom spitting or an extendable neck frill. This animal was easily capable of killing most prey with its jaws and claws alone and its sheer size, at least as an adult, would’ve warded off other dangerous predators. Its crests, the exact shape and full size of which have yet to be determined, were probably visual display structures.