Scientists have discovered a new species of dinosaur that called the Arctic home 70 million years ago.

Nanuqsaurus hoglundi was a — relatively — tiny cousin of the Tyrannosaurus rex.

The unidentified fossilized fragments of the skull and jaw were found in northern Alaska almost eight years ago, in an area known as the Kikak-Tegoseak quarry, on the North Slope close to the Yukon border.

"The big difference between Tyrannosaurus rex and Nanuqsaurus, and Tarbosaurus for example, which is the Asian tyrannosaur, is that Nanuqsaurus is about half the size," said Tony Fiorillo of the Perot Museum of Nature and Science in Texas.

"We feel that's an adaptation to life in the North."

Even though the Arctic was much warmer and more heavily forested in the Cretaceous period than it is now, it still had drastic changes in the lengths of days and nights, depending on the seasons. The 24-hour darkness of winter would have made food scarce at that time of year, and Nanuqsaurusmay have adapted with a smaller body size. 

Nanuqsaurus — named for the native Inupiat word for polar bear — had a skull about 64 centimetres long and stood about two metres high at the hip.

Nanuqsaurus hoglundi fossils

The researchers analyzed bones from the skull and jaw of the new dinosaur. (Anthony R. Fiorillo and Ronald S. Tykoski/Perot Museum of Nature and Sciences)

He inhabited a drastically different Arctic than the one we know today. During the Cretaceous period, the area was a coastal plain that, like now, had the Arctic Ocean to the north and snow-capped mountains to the south. But the Arctic was much warmer, and the area was covered in tall, conifer forests and flowering plants. The temperature would have been similar to western Canada today.

Although Alberta is world-famous for its dinosaur bone beds, Fiorillo said the Arctic remains largely uncharted territory. The 2006 dig produced not one, but two new dinosaur species. Fiorillo and his colleagues have also identified a new species of horned dinosaur from the Kikak-Tegoseak quarry, east of the massive Colville River.

"I can tell you that it's absolutely mind blowing that out of the very same hole in the ground we got not one, but two brand new dinosaurs," he said.

The team also discovered the Pachyrhinosaurus, a cousin of the triceratops.

Did these dinos call Canada home?

At the time, the Brooks range was likely even bigger than it is today and would have blocked the creatures from going south. But there was a coastal plain that would have connected to Canada, Fiorillo said.

"So it's entirely possible to expect to see some of these North Slope dinosaurs into that part of Canada," he said.

Northern Alaska 'littered' with dino fossils

Grant Zazula, paleontologist for the Yukon government, said northern Alaska appears to be "littered" with dinosaur fossils.

The neighbouring territory has a number of sites that are also 65 to 70 million years old but few have been explored.

The territory is known for fossils of ice-age mammals, such as the woolly mammoth, but dinosaurs have been more elusive. Until a few years ago only five fossil bones of dinosaurs had been found along with some dinosaur footprints preserved in the bedrock near the Ross River.

Then a team of paleontologists from Carlton University found the fossil of a plesiosaur, an ancient marine reptile, in the bedrock near the Peel River in northern Yukon.

"But nothing like what they have in Alaska," Zazula said. "We're thoroughly jealous."

Zazula said he hopes the finding shines a light on the paleo potential of the Arctic.

"Alaska is huge, the Arctic of Canada is huge, and there's been so few boots on the ground looking for stuff like this. I think finding a new species like this will just pave the way for future research in the North," he said.

Tyrannosaur sizes

Silhouettes showing approximate sizes of different theropod dinosaurs. They are: A) Nanuqsaurus hoglundi; B) and C) Tyrannosaurus rex; D) Daspletosaurus torosus; E) Albertosaurus sarcophagus; F) and G) Troodon. The scale bar represents one metre. (Anthony R. Fiorillo and Ronald S. Tykoski/Perot Museum of Nature and Sciences)

With files from CBC News