Colorado dinosaur discovery – Allosaurus

Allosaurus dinosaur skeleton
A skeleton of the meat-eating predator Allosaurus greets visitors in the lobby of the San Diego Natural History Museum. The first Allosaurus bones were found in Colorado. | Photo by Sheep81 /

There are two Colorado origins for the Allosaurus, a meat-eating predator from the late Jurassic period.

The first bone was found in Middle Park near Granby by local residents who thought it was a petrified horse’s hoof and turned it over to geologist and explorer Ferdinand Hayden in 1869. Paleontologist Joseph Leidy identified it as half of a tail vertebra.

Paleontologist Othniel Marsh gave the dinosaur the name Allosaurus in 1878, after examining a different set of bones collected from Garden Park north of Cañon City.

An Allosaurus was typically 28 feet long, weighed 2 1/2 tons and stood on two legs, with a large skull and tail, a massive body and a short neck and forearms.

The Allosauraus hunted other large animals, such as the Stegosaurus, as illustrated by the way the skeletons of both dinosaurs are posed in an exhibit at the Denver Museum of Nature & Science.