Ursus maritimus tyrannus

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Ursus maritimus tyrannus
Temporal range: Late Pleistocene
Ursus maritimus tyrannus.jpg
Hypothetical restoration
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Suborder: Caniformia
Family: Ursidae
Genus: Ursus
Species: U. maritimus
Subspecies: U. m. tyrannus
Trinomial name
Ursus maritimus tyrannus
(Kurtén, 1964)

Ursus maritimus tyrannus is an extinct subspecies of polar bear, known from a single fragmentary ulna found in the gravels of the Thames at Kew Bridge, London. It was named by the Finnish paleontologist Björn Kurtén in 1964 and is interpreted to represent a relatively large subadult individual: the ulna is estimated to have been 48.5 cm (19 in) long when complete, "the longest ursine ulna on record",[1] for comparison modern subadult polar bear ulnae are 36–43 cm (14–17 in) long.[1] Dating back to the Late Pleistocene, approximately 70,000 years ago, it is the oldest fossil assigned to the polar bear;[2] however, an unpublished reinvestigation of the fossil suggests that the fossil is actually a brown bear.[3]

Commonly used names include: Pleistocene polar bear or Tyrant polar bear.


  1. ^ a b Kurtén, B. (1964). "The evolution of the polar bear, Ursus maritimus (Phipps).". Acta Zoologica Fennica 108: 1–26. 
  2. ^ Harington, C. R. (2008). "The Evolution of Arctic Marine Mammals". Ecological Applications 18 (2 Suppl): S23–S40. doi:10.1890/06-0624.1. PMID 18494361. 
  3. ^ Ingólfsson, Ólafur; Wiig, Øystein (2009). "Late Pleistocene fossil find in Svalbard: the oldest remains of a polar bear (Ursus maritimus Phipps, 1744) ever discovered". Polar Research 28 (3): 455. doi:10.1111/j.1751-8369.2008.00087.x.