Dilophosaurus was an Early Jurassic theropod dinosaur. It had paired rounded crests on its skull, mostly likely for display. It measured around 6 meters from the tip of the snout to its tail and may have weighed nearly half a ton. This dinosaur has only been discovered in Arizona, USA. The original description was published in 1954 by the renowned paleontologist Samuel Welles ; however, at the time, it was thought to be another genus of theropod (Megalosaurus). In 1970, it was recognized to be distinct and given its own generic name Dilophosaurus (meaning "two-crested lizard"). Welles later redescribed the entire taxon in 1984 in a much more complete paper. Dilophosaurus may be a primitive member of the clade containing both ceratosaurian and tetanuran theropods. Alternatively, some paleontologists classify this genus as a large coelophysoid.
There is another species of Dilophosaurus (D. sinensis) which may or may not belong to this genus. It is possibly closer to the bizarre Antarctic theropod Cryolophosaurus, based on fact that the anterior end of the jugal does not participate in the internal antorbital fenestra and that the maxillary tooth row is completely in front of the orbit and ends anterior to the vertical strut of the lacrimal. This species was recovered from the Yunnan Province of China in 1987 with the prosauropod Yunnanosaurus , and later described and named in 1993 by Shaojin Hu .
Dilophosaurus was also included in the 1993 movie Jurassic Park shown sporting a frilled neck, aiding in its ability to spit poisonous goo. There is no evidence to support this representation. However, director Steven Spielberg did reduce it from its moderately large size to about 3 feet tall, 5 feet long to keep competition low for the main star of the movie, Tyrannosaurus rex.
