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Temporal range: Late Cretaceous, 69.2 Ma
Edmontosaurus Perot Museum.jpg
Reconstructed skeleton, Perot Museum
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Suborder: Ornithopoda
Family: Hadrosauridae
Subfamily: Saurolophinae
Genus: Ugrunaaluk
Mori et al., 2016
Species: U. kuukpikensis
Binomial name
Ugrunaaluk kuukpikensis
Mori et al., 2015

Ugrunaaluk is a dubious genus of saurolophine hadrosaurid which was found in the Arctic of Alaska. It contains the species Ugrunaaluk kuukpikensis.[1][2][3] Its name is derived from the Inupiat words for 'ancient grazer'.

Reconstructed skull of juvenile Ugrunaaluk

From the 1980s onwards, in Alaska more than six thousand bones of hadrosaurid dinosaurs have been uncovered, at the Colville River. They were found north of Umiat in the Liscomb bonebed. At first they were identified as belonging to some member of the Lambeosaurinae.[4] Later, they were referred to Edmontosaurus, more specifically Edmontosaurus regalis, a member of the Saurolophinae.[5] A definite identification was hampered by the fact that most of the bones were of juveniles. In 2014, Hirotsugu Mori solved this problem by statistically determining size classes within the fossil material and comparing the Alaskan bones with known Edmontosaurus annectens specimens of the same size. He concluded that they represented two separate species.[6]

The discovery of the new genus was published online on 22 September 2015 by Hirotsugu Mori, Patrick Druckenmiller and Gregory Erickson.[7] Ugrunaaluk was one of eighteen dinosaur taxa from 2015 to be described in open access or free-to-read journals.[8] However, the identification of Ugrunaaluk as a separate genus was questioned by a 2017 study from Hai Xing and colleagues, who regarded it as a nomen dubium indistinguishable from other Edmontosaurus.[9]


  1. ^ Bakalar, Nicholas (28 September 2015). "New Dinosaur Species That Lived Above Arctic Circle Is Discovered". New York Times. Retrieved 1 October 2015. 
  2. ^ Joling, Dan. "Fossils of new duck-billed, plant-eating dinosaur species found in Alaska, researchers say". Associated Press via US News. Retrieved 23 September 2015. 
  3. ^ Casey, Michael. "New dinosaur species may have left tracks in the snow". CBS News. Retrieved 23 September 2015. 
  4. ^ Brouwers, E.M., Clemens, W.A., Spicer, R.A., Ager, T.A., Carter, L.D., and Sliter, W.V., 1987, "Dinosaurs on the North Slope, Alaska: High latitude, latest Cretaceous environments". Science 237: 1608–1610
  5. ^ Xing, H., Zhao, X., Wang, K. Li, D., Chen, S., Jordan, C.M., Zhang, Y and Xu, X., 2014, "Comparative Osteology and Phylogenetic Relationship of Edmontosaurus and Shantungosaurus (Dinosauria: Hadrosauridae) from the Upper Cretaceous of North America and East Asia", Acta Geologica Sinica 88: 1623–1652
  6. ^ Mori, H., 2014, Osteology, Relationships And Paleoecology Of a New Arctic Hadrosaurid (Dinosauria: Ornithopoda) From the Prince Creek Formation Of Northern Alaska. Unpublished Ph.D. thesis, University of Alaska Fairbanks, Fairbanks 333 pp
  7. ^ Mori, Hirotsugu; Druckenmiller, Patrick S. & Erickson, Gregory M. (2015). "A new Arctic hadrosaurid from the Prince Creek Formation (lower Maastrichtian) of northern Alaska". Acta Palaeontologica Polonica (In press). doi:10.4202/app.00152.2015. 
  8. ^ "The Open Access Dinosaurs of 2015". PLOS Paleo. 
  9. ^ Xing, H.; Mallon, J.C.; Currie, M.L. (2017). "Supplementary cranial description of the types of Edmontosaurus regalis (Ornithischia: Hadrosauridae), with comments on the phylogenetics and biogeography of Hadrosaurinae". PLoS ONE. 12 (4): e0175253. doi:10.1371/journal.pone.0175253.