Dilophosaurus wetherilli, an early theropod (carnivorous) dinosaur and proposed Arizona state fossil, has been recovered from the lower Jurassic Kayenta Formation of northern Arizona. D. wetherilli is known for its two large bony crests on its skull. It made an appearance in Jurassic Park as the infamous "Spitter" which is supported by no scientific evidence. There is a mounted skeleton of Dilophosaurus at the Museum of Northern Arizona in Flagstaff and a sculpture of it outside of the Mesa Southwest Museum in Mesa.

Be aware that some people tend to associate fossil tracks made by large dinosaurs to Dilophosaurus. In fact there is even a type of fossil footprint termed Dilophasaurapus. Despite this, it is impossible to determine what animal made what footprint unless you find the skeleton of an animal at the end of a trackway. Footprints should be associated via the proper ichnogenus - i.e. Eubrontes, Grallator, etc.