Dilophosaurus

Means: Double-Crested Lizard

Period: Early Jurassic, 195-189 Million Years Ago

Region: Arizona, USA

With an estimated body length of around 6 metres, Dilophosaurus is one of the largest predators known from the Early Jurassic of North America.

Fragmentary fossils of this dinosaur were discovered in 1942 in northern Arizona on Navajo Nation territory by a team of palaeontologists from the University of California who were assisted in their excavations by their Navajo Indian guide.  The badly eroded fossil bones were carefully prepared and the first scientific description of this material was published in 1954.  It was erroneously thought that the fossils represented a new type of Megalosaurus – a dinosaur known from the Early Jurassic of Europe.

Expedition team members returned to the site in 1964 and uncovered more fossil bones including a partial skull with unusual bony crests.  This dinosaur was subsequently re-described and named Dilophosaurus in 1970.

Dilophosaurus is one of the most extensively studied of all the carnivorous dinosaurs.  A recent review, published in 2020, suggested that Dilophosaurus was a much more powerful animal than previously thought.  It was probably an apex predator rather than a weak-jawed scavenger.  The crests may have been brightly coloured and were probably used for display or played a role in thermoregulation – helping Dilophosaurus to keep cool, functioning in the same way as the casques on the heads of large, flightless birds such as cassowaries.