Nanuqsaurus
NAN-uk-SORE-us
"polar bear lizard"
Type species Nanuqsaurus hoglundi
- Lived
- 72 to 66 million years ago, Late Cretaceous
- Diet
- Carnivore
- Group
- Theropods, Tyrannosauridae
- Found in
- United States
- Named by
- Fiorillo and Tykoski 2014
Where its fossils were found
The evidence
Today
70 million years ago
Habitat
The Prince Creek landscape in Alaska was a polar delta plain with woodland, ferns and horsetails, subject to long winter darkness. Edmontosaurus and Pachyrhinosaurus lived in the same region.
Field notes
About Nanuqsaurus
What it was like
Nanuqsaurus was a tyrannosaurid, related to Tyrannosaurus, Tarbosaurus, and Daspletosaurus, but known only from a partial skull and a few other bones. Based on what has been found, it appears to have been smaller than many of its southern relatives, though scientists are still debating exactly how small.
Like other tyrannosaurids, it was a bipedal carnivore with a large head, small arms, and powerful jaws.
Its world
Nanuqsaurus lived from about 72 to 66 million years ago, in the Late Cretaceous, in what is now Alaska, further north than almost any other tyrannosaurid known. Its fossils come from the Prince Creek Formation.
It shared this cold, dark-wintered world with the plant eaters Edmontosaurus, Pachyrhinosaurus, and Ugrunaaluk, the dome-headed Alaskacephale, the troodontid Troodon, and the small hunters Dromaeosaurus and Saurornitholestes.
How it was found
Fiorillo and Tykoski named Nanuqsaurus hoglundi in 2014. Only a single fossil find of the genus has been described so far, so much about its full size and appearance is still unknown, and further discoveries could change how it compares to its more familiar relatives.
Field gallery
More views of Nanuqsaurus
Scenes reconstructed from the available fossil evidence.
1 of 7
Lived alongside
Found in the same rock formations
A rock formation can hold fossils laid down millions of years apart, so not every animal here met Nanuqsaurus.
The evidence
The science behind Nanuqsaurus
Which parts of the picture come from its own bones, and which come from its relatives.
From its own fossils
- The original specimen consists of separate pieces of the skull and lower jaw.
- Distinctive features of these skull bones identify it as a tyrannosaurid.
Borrowed from relatives
- The body, tiny arms and balancing tail are restored by comparison with Tyrannosaurus and Tarbosaurus.
- Lips covering the teeth follow comparisons with other theropods.
Still unknown
- Its full adult length and how much smaller it was than southern tyrannosaurids.
- Whether it had feathers, and how much of its body they covered.
- Its color and how it survived the dark winters.
Discovery timeline
- 2014Named itFiorillo & Tykoski
- 2021Its worldDruckenmiller et al.
- 2023Close relativeCullen et al.
Key papers
The research behind what we know of Nanuqsaurus
Named it
Named a northern tyrannosaurid from skull fragments and proposed that it was smaller than its southern relatives.
A Diminutive New Tyrannosaur from the Top of the World. PLoS ONE 9: e91287
Read the paper : A Diminutive New Tyrannosaur from the Top of the World (opens in a new tab)Its world
Tiny bones and teeth show that several dinosaur groups reproduced in Arctic Alaska, supporting year-round residence.
Nesting at extreme polar latitudes by non-avian dinosaurs. Current Biology 31: 3469-3478.e5
Read the paper : Nesting at extreme polar latitudes by non-avian dinosaurs (opens in a new tab)Close relative
Comparisons of teeth and skulls support lips covering the teeth when theropod mouths were closed.
Theropod dinosaur facial reconstruction and the importance of soft tissues in paleobiology. Science 379: 1348-1352
Read the paper : Theropod dinosaur facial reconstruction and the importance of soft tissues in paleobiology (opens in a new tab)
Close relatives
Other members of Tyrannosauridae
Sources: Wikidata