Microtus miurus

From Weksler et al. (2010): "Our results do not support the current taxonomy of singing voles, which recognizes two species (M. abbreviatus and M. miurus; Musser & Carleton, 2005). This is in agreement with previous analyses of cytochrome b from two individuals, one from the Brooks Range (nominally M. miurus), and one from St Matthew Island (M. abbreviatus; Conroy & Cook, 2000b). Cytochrome b data indicate that the population from St Matthew Island, currently referred to Microtus abbreviatus, is not a distinct species from M. miurus; rather, it is a recently isolated population of singing voles dating from a late Pleistocene (Fig. 5, C) expansion of singing voles, as first suggested by Rausch & Rausch (1968). The St Matthew Archipelago was last connected to the North American continent as recently as 13 ka (Hopkins, 1984; Elias et al., 1996; Manley, 2002). The cranial morphological differences found by Rausch & Rausch (1968) between M. miurus and M. abbreviatus could be due to a sampling artefact, as their analyses included a single mainland sample from the Brooks Range. If, however, the differences are in fact real, additional morphological and morphometric analyses should be undertaken to evaluate whether the St Matthew’s populations underwent (or are under) a phenotypic bottleneck or any other insular syndrome process (Van Valen, 1973; Raia & Meiri, 2006). The St Matthew Archipelago represents a unique habitat for singing voles, and its protection may be essential to maintaining the phenotypic diversity of the species.

The synonymization of the two species presents a nomenclatural nuisance: M. abbreviatus Miller, 1899 has priority over M. miurus Osgood, 1901. Thus, the appropriate name for the common singing vole from both mainland Alaska and the St Matthew Archipelago is M. abbreviatus, with M. miurus representing a junior synonym (M. abbreviatus is an apt descriptor of the extremely short tail of the species). In turn, the name Microtus cantator Anderson, 1947, currently considered a junior synonym of M. miurus but whose type locality is less than 50 km from the Wrangell Mountains samples analysed here, is a candidate name for the divergent haplotype lineage sister to all other singing voles (Fig. 3). Testing this hypothesis, which we consider tentative, will require the rigorous analysis of additional specimens from this region of Alaska and north-western Canada as well as relevant type material. To date we have been unable to obtain Canadian samples of M. miurus; the eastern distributional range of singing voles is poorly known, and the status of the isolated population from the Plains of Abraham in the Northwestern Territories is still unknown."

go to Microtus abbreviatus

References

Conroy CJ, Cook JA. 2000a. Phylogeography of a postglacial colonizer: Microtus longicaudus (Rodentia: Muridae). Molecular Ecology 9:165–175.

Elias SA, Short SK, Nelson CH, Birks HH. 1996. Life and times of the Bering land bridge. Nature 382(6586):60-63.

Hopkins DM. 1984. Sea-level history in Beringia during the past 250,000 years. In Beringia in the Cenozoic era; the Bering land bridge and its role in the history of holarctic floras and faunas in the late Cenozoic. Symposium (pp. 3-29).

Manley WF. 2002. Postglacial flooding of the Bering land bridge: a geospatial animation. Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO.

Musser GG, Carleton MD. 2005. Superfamily Muroidea. Mammal species of the world, 3rd edition (ed. by D.E. Wilson and D.M. Reeder), pp. 894–1531. Baltimore (MD, USA): Johns Hopkins University Press.

Raia P, Meiri S. 2006. The island rule in large mammals: paleontology meets ecology. Evolution 60(8):1731-1742.

Rausch RL, Rausch VR. 1968. On the biology and systematic position of Microtus abbreviatus Miller, a vole endemic to the St. Matthew Islands, Bering Sea. Zeitschrift fur Saugetierkunde 33(2):65-99.

Van Valen L. 1973. Patterns and the balance of nature. Evolutionary Theory 1:31-49.

Weksler M, Lanier HC, Olson LE. 2010. Eastern Beringian biogeography: historical and spatial genetic structure of singing voles in Alaska. Journal of Biogeography 37(8):1414-1431.