CRANIUM VARIATIONS BETWEEN THE COMMANDER ISLANDS' ARCTIC FOXES (VULPES LAGOPUS SEMENOVI, VULPES LAGOPUS BERINGENSIS) 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 interspecific variations in the family Canidae. The level of skull variation between the Commander Islands' Arctic foxes and the mainland arctic fox was compared with: (1) skull variations between the Grey fox, Urocyon cinereoargenteus, and the Island fox, U. littoralis; and (2) skull variations between three closely related species the Arctic fox; the Swift fox, V. velox, and the Kit fox, V. macrotis. The present study shows that skull variations between the Commander Islands' Arctic foxes and the mainland Arctic fox correspond to the interspecific level of skull variation in sister species of the genera Vulpes and Urocyon. No general trend in skull variation has been found between the studied species and isolated populations. The presented craniological data support the separation of the Commander Islands' foxes as a distinct species, V. beringensis Merriam 1902, with two subspecies involved: V. b. semenovi Ognev 1931 (Mednyi Island) and V. b. beringensis Merriam 1902 (Bering Island). The Commander Islands' Arctic foxes are a unique part of biological diversity and must be strictly protected.