Dilophosaurus is a genus of theropod dinosaur. It contains a single known species, Dilophosaurus wetherilli, known from fossil remains found in the Kayenta Formation of Arizona, USA. This rock formation has been dated to the early Jurassic Period, about 193 million years ago. Dilophosaurus was among the largest carnivores of its time, about 7 meters long weighing about 500 Kg. The most distinctive characteristic of Dilophosaurus is the pair of rounded crests on its skull, made up of extensions of the Nasal and lacrimal bones. These are considered to be too delicate for anything but display purposes.