Saturday, December 10, 2016

P. perotorum mounted at the Perot Museum

Pachyrhinosaurus (meaning “thick-nosed lizard”) is an extinct genus of centrosaurine ceratopsid dinosaurs 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 the Pachyrhinosaurus. Three species have been identified. P. lakustai, from the Wapiti Formation, the bonebed horizon of which is roughly equivalent age to the upper Bearpaw and lower Horseshoe Canyon Formations, is known to have existed from about 73.5-72.5 million years ago. P. canadensis is younger, known only from the lower Horseshoe Canyon Formation, about 71.5-71 Ma ago. Fossils of the youngest species, P. perotorum, have been recovered from the Prince Creek Formation of Alaska, and date to 70-69 million years ago. The presence of three known species makes this genus the most speciose among the centrosaurines.

Pachyrhinosaurus by


  • May have run as fast as 20 MPH

  • Lived in parts of Canada and Alaska

  • Its name means “thick nosed lizard”

  • 3 species of this dinosaur have been discovered

  • Weighed as much as a Black Rhinoceros


Pachyrhinosaurus is a dinosaur which lived around 70 million years ago during the late Cretaceous Period. It was first discovered in the late 1940s by Charles M. Sternberg, son of famous paleontologists Charles H. Sternberg who found specimens in Alberta, Canada and Alaska, U.S. He also named the fossil, calling it Pachyrhinosaurus—a name which means “thick nosed lizard.”

Pachyrhinosaurus was an herbivore that was approximately 20 to 26 feet long, about 6 feet high and weighed around 2 to 3 tons. Like other dinosaur’s in this dinosaur order, the Pachyrhinosaurus had a large bony frill that came out of the back of its skull. However, what makes this dinosaur different from the other ones in it dinosaur classification is that instead of horns on its nose it had a large bony bump called a “boss.” It did have a pair of horns that grew out of the top of its frill and it may have had horns over its eyes.

Like other herbivores of this time, the Pachyrhinosaurus probably traveled in herds that kept it safe from predators. Paleontologists believe that some of these herds may have had hundreds or thousands of animals in it at one time. If this was indeed the case, then it would have made it quite difficult on predators. It is also likely that these dinosaurs also nested their eggs like modern birds and may have even taken care of them. This has been found to be the case in other dinosaur types such as the Protoceratops and the Styracosaurus.

Paleontologists believe this animal probably lived off of a diet that consisted mainly of palms and cycads and other tough plant material that it could tear off and crush with its beak. It also had cheek teeth that it could use to further masticate this tough plant material, making it easier to digest.

P. perotorum engaged in intraspecific combat. Artistic rendering of Pachyrhinosaurus perotorum engaged in head-butting/pushing behavior. In the first description of Pachryhinosaurus by Sternberg, he speculated that the enlarged nasal boss in the taxon might have been used in head battering or pushing behavior, an idea emphasized by this image of two Pachyrhinosaurus perotorum sparring with their craniofacial bosses, while a third looks on. Author: Karen Carr