Pachyrhinosaurus is an extinct genus of centrosaurine ceratopsid dinosaur from the Late Cretaceous period of North America. The first examples were discovered by Charles M. Sternberg in Alberta, Canada, in 1946, and named in 1950. Over a dozen partial skulls and a large assortment of other fossils from various species have been found in Alberta and Alaska. A great number were not available for study until the 1980s, resulting in a relatively recent increase of interest in Pachyrhinosaurus.
Pachyrhinosaurus
Skulls of the three species compared: P. perotorum (with inaccurate epiparietal placement), P. canadensis, and P. lakustai
Restoration of P. lakustai
P. perotorum mounted at the Perot Museum; note the small forwards pointing epiparietals at the top of the frill, which were inaccurately reconstructed following the original description, while these would actually have faced up like in the other species
Centrosaurinae is a subfamily of ceratopsid, a group of large quadrupedal ornithischian dinosaur. Centrosaurine fossil remains are known primarily from the northern region of Laramidia but isolated taxa have been found in China and Utah as well.
Centrosaurinae
Skull of an unnamed nasutoceratopsin exhibited in the Museo del Mamuth in Chihuahua City, from the municipality of Aldama.
