Morphometric variation in true lemmings (Lemmus) from the Eurasian Arctic

The present study examines cranial variability in true lemmings (Lemmus) ac ross the Eurasian Arctic using a multivariate approach. The work is based o n samples obtained from populations in 11 sites during one field season in the summer of 1994 on the Swedish-Russian Tundra Ecology -94 expedition. Mo rphometric relationships of Palaearctic lemmings based on cranial variables were examined by multiple discriminate function analysis. The results show that all the studied populations form 4 groups: 2 island groups (New Siber ian Islands and Wrangel Island) and 2 mainland groups, designated conventio nally as western and eastern with the boundary along the Lena River. Morpho metric groupings correspond well to the results of mtDNA variation analyses carried out on the same material by V. Fedorov and colleagues at the Depar tment of Genetics, University of Uppsala, Sweden. The distances between the groups obtained with different methods differ notably. Some of the groups distinguished in both analyses are consistent with the current Lemmus taxon omy, whereas distinction between the western and eastern mainland groups re vealed both by genetic and morphologic methods till now have not been taken into account. The data from the present study provide a sound basis For th e reestablishment of the subspecies L. sibiricus bungei Vinogr., 1925, in t he Arctic mainland tundra. This subspecies had previously been defined from insufficient material and was, therefore, not recognized in subsequent stu dies. The distribution range of L. s. bungei covers tundra from the eastern shore of the Lena River up to the western shore of the Kolyma River. The r ange of the nominal subspecies L. s. sibiricus should, therefore, be regard ed as including the tundra east of the White Sea up to the Lena River.