Pachyrhinosaurus

pachyrhinosaurus
Pachyrhinosaurus (Karen Carr).

Name:

Pachyrhinosaurus (Greek for "thick-nosed lizard"); pronounced PACK-ee-RYE-no-SORE-us

Habitat:

Woodlands of western North America

Historical Period:

Late Cretaceous (70 million years ago)

Size and Weight:

About 20 feet long and 2-3 tons

Diet:

Plants

Distinguishing Characteristics:

Thick bump on nose instead of nasal horn; two horns on top of frill

 

About Pachyrhinosaurus

Its name notwithstanding, Pachyrhinosaurus (Greek for "thick-nosed lizard") was an entirely different creature from the modern rhinoceros, though these two plant-eaters do have a few things in common.

Paleontologists believe Pachyrhinosaurus males used their thick noses to butt one another for dominance in the herd and the right to mate with females, much like modern-day rhinos, and both animals were approximately the same length and weight (though Pachyrhinosaurus may have outweighed its modern counterpart by a ton or two).

That's where the similarities end, though. Pachyrhinosaurus was a ceratopsian, the family of horned, frilled dinosaurs (the most famous examples of which were Triceratops and Pentaceratops) that populated North America during the late Cretaceous period, only a few million years before the dinosaurs went extinct. Oddly enough, unlike the case with most other ceratopsians, the two horns of Pachyrhinosaurus were set on top of its frill, not on its snout, and it had a fleshy mass, the "nasal boss," in place of the nasal horn found in most other ceratopsians. (By the way, Pachyrhinosaurus may turn out to be the same dinosaur as the contemporary Achelousaurus.)

Somewhat confusingly, Pachyrhinosaurus is represented by three separate species, which differ somewhat in their cranial ornamentation, especially the shape of their unflattering-looking "nasal bosses." The boss of the type species, P. canadensis, was flat and rounded (unlike that of P. lakustai and P. perotorum), and P. canadensis also had two flattened, forward-facing horns on top of its frill.

If you're not a paleontologist, though, all three of these species look pretty much identical!

Thanks to its numerous fossil specimens (including over a dozen partial skulls from Canada's Alberta province), Pachyrhinosaurus is quickly climbing the "most popular ceratopsian" rankings, though the odds are slim that it will ever overtake Triceratops. This dinosaur got a big boost from its starring role in Walking with Dinosaurs: The 3D Movie, released in December 2013, and it has featured prominently in the Disney movie Dinosaur and the History Channel TV series Jurassic Fight Club.