Scientists say the rounded crests on its skull were probably used for display. The first specimens of the Dilophosaurus were found in Arizona in 1942. In 1964, another specimen was found in the same area. The Dilophosaurus walked on its strong hind legs. It measured about 23 feet long and may have weighed up to 2,200 pounds. This dinosaur is one of those featured in the movie Jurassic Park, where it is shown at smaller size and spits venom (there is no scientific evidence for this action).