Dilophosaurus is a genus of dinosaur belonging to the family Dilophosauridae. It lived approximately 193 to 188 million years ago, during the Early Jurassic, in what is now North America. The first fossils of Dilophosaurus were discovered in the 1940s and 1950s, providing paleontologists with valuable insights into this unique theropod. It was a close relative to Coelophysis, and like the earlier dinosaur, it had four fingers each hand. The fourth finger however, was very small and probably had no function.

Dilophosaurus was a medium-sized dinosaur, estimated to have reached lengths of around 6 to 7 meters. It possessed a slender build, long hind limbs, and well-developed arms with sharp claws. One of its most distinguishing features was a pair of crests on its skull, which likely played a role in visual displays rather than serving a defensive or combat purpose.

While Dilophosaurus is often portrayed with a frill and venom-spitting capabilities in popular culture, these characteristics are not supported by fossil evidence. The true nature of its crests and its behavior remains a subject of ongoing scientific investigation and debate. Current research suggests it was a fast and agile predator, utilizing its sharp teeth and grasping claws to capture and subdue its prey.