Colepiocephale

Colepiocephale was a small pachycephalosaur that lived in Alberta during the Late Cretaceous period. Found within the Foremost Formation, it represents one of the earliest known North American pachycephalosaurids with a fully developed bony dome. Reaching an estimated length of around two metres and weighing under forty kilograms, it was a swift bipedal herbivore that browsed close to the forest floor. The dome is distinctive because the lateral and posterior shelves found in later relatives are largely reduced, giving the skull a tall, steep-sided profile resembling a clenched fist or knuckle. Like its relatives, its durable skull bones are frequently the only elements preserved in river channel deposits. Colepiocephale helps palaeontologists map the early radiation of dome-headed ornithischians across the ancient landmass of Laramidia.

It is one of the oldest known fully domed pachycephalosaurs discovered in North America.

Where and when

Colepiocephale lived in the Late Cretaceous, from 80.5 to 77.5 million years ago (Campanian age). Its remains come from Canada, in the Foremost Formation.

The numbers

Length 1.8 m (estimates run from 1.5 to 2 m). Mass about 28 kg. Hip height about 0.6 m. That is 1.1 human-lengths, or 0.16 of a double-decker bus. These are estimates from fragmentary remains; fields marked estimated by the site are length, mass, hip height.

Compare Colepiocephale with a bus Place on the timeline