Toothy Tyrannosaurus rex had a tiny cousin, suggests new research.
The dwarf dino, named Nanuqsaurus hoglundi, lived 70 million years ago in Alaska, according to a new study, published in the journal PLOS ONE.
The skull for the newly identified dinosaur measured 25 inches long, compared to 60 inches for T. rex. The new dino was a tyrannosaur though, conclude researchers Anthony Fiorillo and Ronald S. Tykoski from the Perot Museum of Nature and Science and their colleagues.
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Tyrannosaurs marched around on two legs, loved meat and had a large skull relative to the size of their body, which was balanced by a hefty, long tail.
T. rex lived throughout what is now western North America. This latest discovery, however, is at the extreme north of the known range. The fossils were recovered from Prince Creek Formation in Northern Alaska.
"The ‘pygmy tyrannosaur' alone is really cool because it tells us something about what the environment was like in the ancient Arctic," Fiorillo said in a press release. "But what makes this discovery even more exciting is that Nanuqsaurus hoglundi also tells us about the biological richness of the ancient polar world during a time when the Earth was very warm compared to today."
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The smaller body size of N. hoglundi compared to most tyrannosaurs from lower latitudes may reflect an adaptation to variability in resources in the arctic seasons. In other words, things were probably feast or famine for the dinosaur, which still somehow managed to eke out an existence.
There are a couple of theories as to how dinosaurs survived cold Arctic winters. One is that they hibernated. The other is that they migrated south during the coldest periods. There isn't strong evidence for the latter, though.
Remains of duck-billed dinosaurs have been found in Alaska. These dinosaurs were thought to have lived in groups or even herds, so they could have huddled to stay warm. That could have been a mouth-watering sight for a predator like the newly discovered tyrannosaur.
Illustration: Karen Carr