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Researchers uncover massive pachyrhinosaur skull

Dinosaur discovery among largest ever of its kind in Alberta

A gargantuan pachyrhinosaur skull was recently uncovered in the Badlands of Alberta by University of Calgary paleontologists. The last discovery of this type in the same region dates back to more than 50 years ago when only a partial skull was collected.

Front oblique view of massive skull of pachyrhinosaur dinosaur (end of snout is left). Large bony nasal boss atop the snout and eye sockets.Front oblique view of massive skull of pachyrhinosaur dinosaur (end of snout is left). Large bony nasal boss atop the snout and eye sockets.

The new specimen was found last October in the Town of Drumheller, Alberta by Darla Zelenitsky, assistant professor at the University of Calgary in the Department of Geoscience, and a research assistant.

During a routine fossil search, the researchers realized that what initially looked like a small bumpy rock exposed at the surface was actually the skull of the horned dinosaur.

Paleontologist Zelenitsky with pachyrhinosaur skull (side view). Paleontologist Zelenitsky with pachyrhinosaur skull (side view).

“It is very rare to find such a complete skull specimen of this size and type in the region,” says Zelenitsky. “Based on our preliminary estimates, the skull would have been well over two metres long and was likely of a mature or older individual. The skull of this animal has an enormous bony structure over the snout that would have made for a very strange looking individual.”

Pachyrhinosaurs were four-legged horned herbivores that lived about 70 million years ago in what are now Alberta and Alaska. This dinosaur reached more than six metres in length and its head was adorned with large bony bumps, horns, and a large frill at the back extending over the neck. The features on the head were likely used for mate competition, perhaps in display or combat.

Field excavation in Alberta’s badlands of pachyrhinosaur skull in October 2013.Field excavation in Alberta’s badlands of pachyrhinosaur skull in October 2013.

Following the discovery, Zelenitsky and her research group removed five to six tons of rock over 10 days to extract the skull from Alberta's Badlands. The past several months were spent preparing it in the laboratory in order to carefully remove the rock encasing the bone.

“So far, the upper part of the skull has been exposed and the skull will be flipped over to prepare the lower part, including the jaws,” explains Zelenitsky. “There are still many months of work necessary in order to clean the entire skull.”

After the skull has been completely cleaned, it will be scientifically studied.

“Our initial goal will be to determine if this specimen represents a new species,” adds Zelenitsky. “Following that, the specimen will be measured and scanned to help document how the skull of pachyrhinosaurs changed during growth, particularly in the later stages of life. The nature of this discovery will certainly add to our understanding of the biology of pachyrhinosaurs,” she concludes.

The researcher intends to resume the search for more bones at the site of the find in the coming months. The collected specimen will eventually go on display at the University of Calgary.

Zelenitsky is a leading paleontologist in Canada. In 2012, she published findings on the discovery of fossils of the first feathered dinosaurs from North America. This significant discovery was selected as one of the 10 best recent dinosaur discoveries by WIRED Magazine.