The Pachyrhinosaurus (Greek meaning “thick-nosed lizard”) is a genus of centrosaurine ceratopsid dinosaurs from the Late Cretaceous Period (Campanian stage) of what is now Canada. Pachyrhinosaurus was a large dinosaur, closely resembling the Triceratop except for the large, flat brow horns and the distinctive hump on its nose.

Key Facts

Pachyrhinosaurus pronunciationpack-ee-RINE-oh-sore-us
What does Pachyrhinosaurus mean?Thick-nosed lizard
Dinosaur typeCeratopsian
On the menuHerbivorous
Length8 meters (26 feet)
Height2 m (7 feet )
Weight4 tons (about 8000 lbs)
Life expectancy40-45 years
Legs used to get aroundQuadruped
Estimated top speed24 km/h (15 mph)
When they livedLate Cretaceous era 76-74 million years ago
Where they have been found?Canada

When & Where

In 1946, Charles M. Sternberg (1885-1981) discovered Pachyrhinosaurus in the Dinosaur Park Formation, Drumheller, Alberta, Canada.

In a scientific paper published in 1950, Sternberg formally described and named the Pachyrhinosaurus lakustai. The name Lakustai is derived from the name of the Polish-Canadian paleontologist Zbigniew Lakusta, who discovered the type specimen.

In 1958, Sternberg described Pachyrhinosaurus canadensis based on material found in the Horseshoe Canyon Formation, Drumheller, Alberta.

A third species of Pachyrhinosaurus, Pachyrhinosaurus perotorum, was described in 1993 on the basis of a well-preserved skull and associated skeleton from the Prince Creek Formation, Alaska.

In 2010, Scott Persons and Philip J. Currie named the fourth species: Pachyrhinosaurus torosus. Their fossil material came from the Bardyevka bonebed in the North Slope Borough, Alaska.

Size & Weight

This large dinosaur could grow to be 8 meters (26 feet) long and 2 m (6.5 feet) tall at the hip. It weighed 4 tonnes (about 8,800 pounds), almost the same size as a Majungasaurus.

Mobility & Diet

Pachyrhinosaurus was a herbivore, eating plants and shrubs. It had a beak like other ceratopsians and probably used its teeth and beak to crop vegetation.

Scientists believe that Pachyrhinosaurus mostly fed on palms and cycads, as these plants have been found in the Dinosaur Park Formation in Drumheller.

Pachyrhinosaurus was a quadruped, moving around on all four legs. It could walk or run at a top speed of about 24 km/h (15 mph), an estimate based on the size of its leg bones.

Interesting Points

  • The function of the Pachyrhinosaurus’s hump is still being debated. It could have been used to attract mates, much like the antlers of deer. Or, the hump may have been used to make the animal look larger and more intimidating to predators or rivals.
  • These dinosaurs frequently fought with each other or with predators. Some Pachyrhinosaurus fossils were found with broken ribs or rib injuries that had healed over time.
  • Pachyrhinosaurus lived in herds. In 1974, a science teacher discovered a mass grave of Pachyrhinosaurus with up to 3500 bones and 14 skulls along Pipestone Creek in Alberta. The fossils were of different sizes, which suggests that the dinosaurs of different ages and genders lived together in groups.

Featured Image Credit: Nobu Tamura, CC BY 3.0, via Wikimedia Commons