Styracosaurus, artwork. Styracosaurus was a dinosaur belonging to the Ceratopsidae family and was closely related to Triceratops. It lived during the Late Cretaceous, 76.5 - 75 million years ago. It measured up to 5.5 metres in length and its head was crowned with horns protruding from a frill. It is depicted here scavenging on a carcass. Recent theories have speculated that Styracosaurus may have had an omnivorous diet instead of being strictly vegetarian.