Temporal range: Late Cretaceous
Tumblr nw0w0c2r5y1uswz2lo1 1280.jpg
An artist's illustration of Nanuqsaurus hoglundi
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Suborder: Theropoda
Family: Tyrannosauridae
Subfamily: Tyrannosaurinae
Genus: Nanuqsaurus
Fiorillo & Tykoski, 2014
Species: N. cheloniformis
Binomial name
Nanuqsaurus hoglundi
Fiorillo & Tykoski, 2014

Nanuqsaurus is a genus of pygmy sized dinosaur whose name means polar bear lizard[1] It is only known from two specimens, DMNH 21461, a partial Skull roof found in Alaska and DMNH 6666 a partial snout also found in Alaska in 1995 but was previously referred to as Tyrannosaurus. This dinosaur may have only grew to about 6 m (19.7 ft) long, which was half the size of an average Tyrannosaurus.

Naming & Discovery

In 2006, at the Kikak-Tegoseak Quarry, in North Slope Borough in the north of Alaska, fossils were found of a medium-sized theropod, with an estimated skull length of 600–700 mm (24–28 in). These were first referred to Gorgosaurus and later to Albertosaurus. After preparation in the Perot Museum of Nature and Science (Dallas Museum of Natural History) it was recognised these represented a species new to science. The holotype, DMNH 21461, has been found in a layer of the Prince Creek Formation, dated at 69.1 million years. It consists of a partial skull with a lower jaw, which were found very close together. It contains the nasal branch of the right maxilla; a partial skull roof including partial parietals, frontals and a right laterosphenoid; and the front of the left dentary. The specimen is from a fully mature individual, as it has a smooth nasal contact.

Nanuqsaurus was first described and named by Anthony R. Fiorillo and Ronald S. Tykoski in 2014. The type species is Nanuqsaurus hoglundi. The generic name is derived from the Iñupiaq word for "polar bear", nanuq, and the Greek word sauros, meaning "lizard". The specific name honours the philanthropist Forrest Hoglund, for his work on philanthropy and cultural institutions.


Nanuqsaurus has been estimated to have been about six meters (twenty feet) long, about half the length of Tyrannosaurus rex. This diminutive size was postulated by Fiorillo and Tykoski as being an adaptation to its high-latitute habitat.


Nanuqsaurus bears a particularly shaped ridge on its head indicating the carnivore was related to Tyrannosaurus rex. The length of the reconstructed skull, based on the proportions of related animals, is 60–70 cm (24–28 in).

Classified as a tyrannosaurine, Nanuqsaurus is diagnosed by: a thin, rostrally forked, median spur of the fused parietals on the dorsal skull roof that overlaps and separates the frontals within the sagittal crest, frontals with a long, rostrally pointed process separating the prefrontal and lacrimal facets and that the first two dentary teeth are much smaller than the dentary teeth behind them


The holotype material of Nanuqsaurus.


The skull would have been around 50 cm (1.65 feet) when complete.

What did Nanuqsaurus eat?

Nanuqsaurus lived in Alaska so it hunted Ugrunaaluk and young Pachyrhinosaurus. In the summer, the prey numbers would have expleded but they declined in the winter.


Nanuqsaurus makes its first media appearance in the new Dino Dan Series Dino Dana.



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