Temporal range: Upper Cretaceous
|Skull of Pachycephalosaurus at the Oxford University Museum of Natural History.|
Brown & Schlaikjer, 1943
P. wyomingensis (Gilmore, 1931) (type)
Pachycephalosaurus was a genus of ornithischian dinosaur which lived during the last five million years of the Upper Cretaceous. It lived in what is now North America. Pachycephalosaurus was a member of the Pachycephalosaurid family. This dinosaur is only known from a single skull and a few extremely thick skull roofs. From this it is estimated that its length was about 4.5 to 5 metres long (about 15 feet). It is the largest known pachycephalosaur.
Scientists do not yet know for sure what these dinosaurs ate. Having very small, ridged teeth they could not have chewed tough, fibrous plants as effectively as other dinosaurs of the same period. It is assumed that pachycephalosaurs lived on a mixed diet of leaves, seeds, fruit and insects. The sharp, serrated teeth would have been very effective for shredding plants.