Microtus oregoni (Bachman, 1839)

Guy G. Musser & Michael D. Carleton, 1993, Order Rodentia - Family Muridae, Mammal Species of the World (2 nd Edition), Washington and London: Smithsonian Institution Press, pp. 501-755 : 527

Microtus oregoni (Bachman, 1839) . J. Acad. Nat. Sci. Philadelphia, 8:60.

TYPE LOCALITY: USA, Oregon, Clatsop Co., Astoria .

DISTRIBUTION: Moist coniferous forest seres of Pacific Northwest, from SW British Columbia, Canada, south to NW California, USA.

SYNONYMS: adocetus, bairdi , cantwelli, morosus , serpens .

COMMENTS: Subgenus Mynomes , sole member of oregoni species group sensu Zagorodnyuk (1990) . Type species of Chilotus , conventionally recognized as a subgenus of Microtus (see Anderson, 1959, 1960; Bailey, 1900), and occasionally including Old World M. socialis as a comember ( Chaline, 1974; Ognev, 1964) or not ( Anderson, 1959). Hooper and Hart (1962), however, found the morphological evidence insufficient to warrant subgeneric segregation of oregoni from North American species of Microtus , a viewpoint sustained by genetic distance comparisons ( Moore and Janecek, 1990) and reflected in the classification of Zagorodnyuk (1990). Diploid number and sexdetermining mechanism unique among North American Microtus studied ( Ohno et al., 1963). See Carraway and Verts, 1985 (Mammalian Species, 233).