Microtus richardsoni DeKay 1842

Wilson, Don E. & Reeder, DeeAnn, 2005, Order Rodentia - Family Cricetidae, Mammal Species of the World: a Taxonomic and Geographic Reference (3 rd Edition), Volume 2, Baltimore: The Johns Hopkins University Press, pp. 955-1189 : 1014

Microtus richardsoni DeKay 1842

Microtus richardsoni DeKay 1842 , Zoology of New York, Part I, Mammals: 91.

Type Locality: Canada, Alberta Prov., vicinity of Jasper House (as interpreted by Bailey, 1900:60).

Vernacular Names: North American Water Vole.

Synonyms: Microtus arvicoloides (Rhoads 1894) ; Microtus myllodontus Rasmussen and Chamberlain 1959 ; Microtus principalis Rhoads 1895 .

Distribution: Wet subalpine and alpine meadows of Rocky Mountains, from S British Columbia and Alberta, Canada, to W Wyoming and C Utah, USA; and of Cascade Mountains, from SW British Columbia south through WC Oregon.

Conservation: IUCN – Lower Risk (lc).

Discussion: Senior synonym of the type (= arvicoloides ) of Aulacomys . In early classifications ( Bailey, 1900; Miller, 1896), richardsoni was placed with Old World water voles in the subgenus Arvicola (including Aulacomys ) of Microtus , a relationship reaffirmed by Hooper and Hart (1962) and followed by others, with Arvicola employed either at the subgeneric ( Hall, 1981) or generic level (Jones et al., 1975). Substantial evidence argues the retention of richardsoni within Microtus and the restriction of Arvicola to Old World forms ( Carleton, 1981; Conroy and Cook, 2000 a; Gromov and Polyakov, 1977; Hinton, 1926 a; Jannett, 1997; Koenigswald, 1980; Repenning, 1980; Zagorodnyuk, 1990). Hoffmann and Koeppel (1985) further suggested the autochthonous origin of M. richardsoni in North America from an early stock that also gave rise to M. xanthognathus , an idea consistent with the biochemical similarity of richardsoni to certain New World Microtus ( Nadler et al., 1978) and with Zagorodnyuk's (1990) usage of the subgenus Aulacomys ; cytochrome b sequence data, although also supporting a North American origin, disclose nearest kinship to M. (Pitymys) pinetorum ( Conroy and Cook, 2000 a) . See Ludwig (1984, Mammalian Species, 223).