Cranium Variations between Arctic Foxes (Vulpes lagopus semenovi, Vulpes lagopus beringensis) on the Commander Islands and the Mainland Arctic Fox (Vulpes lagopus lagopus) in Comparison with Interspecies Variations in the Genera Urocyon and Vulpes (Canidae)

The Arctic foxes, Vulpes lagopus, from the Commander Islands are known to be well differentiated in skull morphology from the mainland population. Our study is the first to compare this differentiation with interspecies variations in the family Canidae. The level of skull variations between the Arctic foxes of the Commander Islands and the mainland Arctic fox was compared with skull variations between (1) the gray fox, Urocyon cinereoargenteus, and the island fox, U. littoralis; and (2) three closely related species of the Arctic fox: the swift fox, V. velox, and the kit fox, V. macrotis. The skull variations between the Arctic foxes of the Commander Islands and the mainland Arctic fox were shown to correspond to the interspecies level of skull variation in sister species of the genera Vulpes and Urocyon. No general trend in skull variation has been found between the species studied and isolated populations. The craniological data presented support the separation of foxes from the Commander Islands as a distinct species, V. beringensis Merriam 1902, with two subspecies: V. b. semenovi Ognev 1931 (Medny Island) and V. b. beringensis Merriam 1902 (Bering Island). The Arctic foxes of the Commander Islands are a unique part of the biological diversity and must be strictly protected.