Chasmosaurinae

Chasmosaurus belli ROM 843, Royal Tyrrell Museum of Paleontology. Late Cretaceous 75-74.5 millions years ago. Found at Dinosaur Provincial Park, Alberta, and prepared at the Royal Tyrrell Museum of Paleontology, Drumheller, Alberta.

Chasmosaurus belli ROM 843, Royal Tyrrell Museum of Paleontology. Late Cretaceous 75-74.5 millions years ago. Found at Dinosaur Provincial Park, Alberta, and prepared at the Royal Tyrrell Museum of Paleontology, Drumheller, Alberta.

Achelousaurus horneri skull, collected in Glacier County, Montana, at the Museum of the Rockies in Bozeman, Montana. The Ceratopsidae are those dinosaurs with head frills. There are three large subgroups of Ceratopsidae: Centrosaurinae, Ceratopsinae, and Chasmosaurinae. The Triceratopsini are a "tribe" of the Chasmosaurinae -- a genus so vast that it gets the special name "tribe". The Pachyrhinosaurini are a "tribe" within the Centrosaurinae. Achelousaurus is a genus within the Pachyrhinosaurini. So far, only three skulls and some limited skeletal remains have been collected anywhere in the world -- and all of them in Montana. Their bony frills are quite similar to the Styracosaurus albertensis, although their other skull features (such as big bony bosses on the nose and behind the eyes) are not.