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

Nanuqsaurus hoglundi is a tiny cousin of the Tyrannosaurus rex that lived in northern Alaska, close to the Yukon border on the Beaufort Sea.

Tony Fiorillo of the Perot Museum of Nature and Science in Texas says the fossil fragments of the skull and jaw were found in what is known as the Prince Creek Formation.

Fiorillo says the tiny tyrranosaur was about half the size of the T. rex,  Its skull was about 64 centimetres long and it stood less than three metres high.

His team believes the creature was smaller because it had to adapt to the arctic climate of the day, which was warmer and more heavily forested in the Cretaceous period.

The finding is published in the latest edition of the scientific journal PLOS ONE.