Geographic Variability of the Shape of the Toothrow in the Arctic Fox (Vulpes lagopus L. 1758): The Role of Asymmetry and Allometry.

The geographic variability of the shape of the toothrow of the upper cheek was studied in Arctic foxes using the methods of geometric morphometrics. The geographical variability was studied using 288 specimens from 19 localities in North America, Eurasia, and islands of the Pacific and Arctic oceans. A significant monomorphism of the toothrow was demonstrated for all mainland Arctic foxes, as well as Arctic foxes from Greenland and St. Lawrence Island. The Arctic foxes of four Pacific island populations (two Commander and two Pribilof) differ significantly from the mainland Arctic foxes by the shape of the toothrow. At the same time, Arctic foxes of Mednyi Island, Bering Island, and the Pribilof Islands also differ from each other. The Arctic fox from Mednyi Island has the shortest and most widely spaced toothrow, as well as very large teeth. On the contrary, the Arctic fox from the Pribilof Islands has the smallest teeth. Allometry does not play a significant role in the formation of geographic variability in the toothrow in Arctic foxes. A high level of fluctuating asymmetry was detected in Arctic foxes of Mednyi Island and St. George Island as compared with its level in other Arctic fox populations. It is most likely that, for the Arctic fox from Mednyi Island, this is caused by known low genetic diversity of the population due to passage of an extreme population bottleneck in the recent past. It was suggested that the factors of fluctuating asymmetry affecting the Arctic foxes of Mednyi and St. George islands are identical. [ABSTRACT FROM AUTHOR]