Pachyrhinosaurus

Pachyrhinosaurus was a plant-eating dinosaur that lived in prehistoric Alberta, Canada, and Alaska, USA.

It was a member of the ceratopsian dinosaur groupopens in a new window, which also includes the well-known horned dinosaur Triceratopsopens in a new window.

But unlike Triceratops, Pachyrhinosaurus didn’t have a nose horn. Instead, it had a large, flattened bony structure on its snout and a smaller one above its eyes. These structures are called bosses.

In each fossil site where Pachyrhinosaurus remains are found, there’s evidence of adult and juvenile Pachyrhinosaurus buried together. This means they likely moved in herds to protect and care for their young.

The first Pachyrhinosaurus fossils were found in 1946 in Alberta, Canada, by a scientist named Charles Mortram Sternberg. In 1950, he published his work and officially named the dinosaur Pachyrhinosaurus.

Since then, more Pachyrhinosaurus remains have been found in Alaska, USA.

Pachyrhinosaurus lived during the Late Cretaceous Period, specifically between about 74 and 68 million years ago.

In Alberta, Canada, the environment at that time was very warm with many coastal plains and forests.

While Alaska, USA, was also warmer than it is today, it was subject to some seasonal variations during the Late Cretaceous. These included periods of cold and darkness in the winter.

Although Pachyrhinosaurus and Triceratops were both ceratopsian dinosaurs, they weren’t very closely related.

Triceratops was a member of the chasmosaurine subgroup, which tended to have longer frills and brow horns. But Pachyrhinosaurus belonged to the centrosaurine subgroup, which often had larger nose horns or bosses.

There are no known skin fossils for Pachyrhinosaurus, so we can’t say for sure whether this dinosaur had feathers.

We know that some early relatives had feather-like structures. Psittacosaurusopens in a new window, an early ceratopsian, had quill-like filaments. But there’s no evidence that later animals such as Pachyrhinosaurus had them.

We do have scaly skin evidence for several other ceratopsian dinosaurs, such as Centrosaurusopens in a new window, Chasmosaurusopens in a new window and Triceratops.

Pachyrhinosaurus could grow to be about six to eight metres long. That’s about as long as two ordinary cars parked one behind the other.

It was among the largest ceratopsian dinosaurs and may have been similar in size to Triceratops.