Nanuqsaurus

Nanuqsaurus was small for a tyrannosaur, with an estimated skull length of only 600 to 700 millimeters (about 2 feet) in adults.1

It lived at a paleolatitude of about 80 to 85 degrees north, meaning it experienced months of continuous darkness in winter.3

Its name comes from the Iñupiaq word 'nanuq' for polar bear, because it was a top predator in a cold, seasonal environment.1

Nanuqsaurus had a distinctive skull feature: the first two teeth in its lower jaw were much smaller than the ones behind them, which helped it bite in a unique way.1

It was closely related to the famous Tyrannosaurus rex, but much smaller, possibly because food was scarce in its Arctic habitat.1

The only known fossil is a partial skull, found in 2006, and it was initially mistaken for a different dinosaur called Gorgosaurus.1