The real Dilophosaurus was bigger than Jurassic Park's and never spat venom
Moviegoers remember Dilophosaurus as a small, frilled dinosaur that sprays venom. Neither the frill nor the spit has any fossil support, and the real animal was about 7 metres long and weighed some 400 kilograms, making it the largest land animal known in North America in its day, around 186 million years ago.
Its story starts with a Navajo man, Jesse Williams, who found bones in northern Arizona in 1940. In the summer of 1942 he led members of a University of California expedition to the site near Tuba City, where three skeletons lay in purplish shale in a rough triangle. The best was nearly complete; the third was so weathered that only scraps of vertebrae remained. Cleaning and mounting the first took three men two years.
Samuel Welles first named it in 1954 as a species of Megalosaurus, calling it wetherilli after the explorer John Wetherill. In 1964 he returned to date the rock and found a larger skeleton about 400 metres from the original quarry. That specimen showed that the animal carried two thin, arched crests on its skull; one had earlier been mistaken for a misplaced piece of cheekbone. Recognising that nothing else then known had such crests, Welles created a new genus in 1970, Dilophosaurus, meaning two-crested lizard.
It was slender and lightly built, with a narrow snout, a kink in the upper jaw below the nostril, and long, thin, curved teeth. Its hands had a large claw on a short, strong first finger. The crests were too fragile for fighting and may have served for display. It may have grown 30 to 35 kilograms a year when young, and the type specimen shows healed injuries. Connecticut, where its footprints are attributed, made it the state dinosaur.
Despite being found so long ago, it long remained poorly understood, partly because earlier studies failed to separate original bone from reconstruction. In 2020 Adam Marsh and Timothy Rowe redescribed it, relocating the original quarry with help from a relative of Jesse Williams, and Marsh called it the best worst-known dinosaur.
Source: Dilophosaurus
