Stegoceras

What it was like

Stegoceras was a small plant eater about 2.4 meters (8 feet) long with a thick bony dome on top of its head. It walked on two legs and had small, leaf-shaped teeth.

Scientists have long debated what the dome was for. It may have been used for head-butting or shoving rivals, or mainly for display.

Its world

It lived about 84 to 72 million years ago, in the Late Cretaceous, in what are now Alberta and Montana, with other remains from New Mexico and elsewhere. Many of its fossils come from the Dinosaur Park and Oldman formations.

It shared those lands with the tyrannosaurs Gorgosaurus and Daspletosaurus and smaller hunters like Saurornitholestes and Troodon.

How it was found

Lambe named Stegoceras in 1902. The type species is Stegoceras validum. About 43 finds are known, mostly the tough domes, which survive better than the rest of the skeleton.