Diabloceratops dinosaur. Computer artwork of a one tonne, 20 foot (6 metres) long Diabloceratops wandering in a forest during the Late Cretaceous period (around 65 to 100 million years ago), in what is now Utah in the United States. Like the better known Triceratops, Diabloceratops was a Ceratopsid, a large four-legged plant-eating dinosaur characterized by beaks, rows of shearing teeth in the back of the jaw, and elaborate horns and frills.