when was it discovered?
In 1940.
Dilophosaurus
 Three skeletons were discovered in northern Arizona in 1940, and the two best preserved were collected in 1942
what is dilophosaurus? A genus of theropod dinosaur.
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Dilophosaurus [SEP] Introduction
Dilophosaurus ( ) is a genus of theropod dinosaurs that lived in what is now North America during the Early Jurassic, about 193 million years ago. Three skeletons were discovered in northern Arizona in 1940, and the two best preserved were collected in 1942. The most complete specimen became the holotype of a new species in the genus "Megalosaurus", named "M. wetherilli" by Samuel P. Welles in 1954. Welles found a larger skeleton belonging to the same species in 1964. Realizing it bore crests on its skull, he assigned the species to the new genus "Dilophosaurus" in 1970, as Dilophosaurus wetherilli.