Microtus oeconomus (Pallas, 1776). Reise Prov. Russ. Reichs., 3:693.

TYPE LOCALITY: U.S. S. R., R.S.F.S. R., Omsk. Obi., Ishim Valley.

DISTRIBUTION: N. Palearctic, from Scandinavia and the Netherlands east to Chukotka (U.S. S.R.); south to S.E. Germany, Hungary, Ukraine, Kazakhstan, Tibet, Szechwan, and Heilungkiang (China) (SW), and Ussuri region; Kurile Islands and Sakhalin; St. Lawrence Isl. (Bering Sea); Alaska (U.S.A.); Yukon and Northwest Territories (Canada).

COMMENT: Subgenus Sumeriomys (= Suranomys Chaline, 1974), see Argyropulo, 1933, Z. Saugetierk., 8:180-182; or Microtus; see Gromov and Polyakov, 1977:295, and Gromov and Baranova, 1981:209. The taxon limnophilus, an isolate described from the Tsaidam, Tsinghai, China, is usually assigned to this species (see Corbet, 1978:115), but may be a distinct species; see Orlov et al., 1978, [Geogr. and Dynamics of Plants and Anim. in the Mongolian People's Republic], p. 149- 164; also see Sokolov and Orlov, 1980:151, who included Sinkiang, Kansu, N.W. China, and W. Mongolia in the distribution of limnophilus, which they considered a distinct species. Includes ratticeps; see Corbet, 1978:115. Ognev, 1950, [Mammals of the U.S. S.R. and Adj. Count.], Vol. 7, Rodents, Engl. Trans., 1964:1 -626, and Ellerman, 1941, differed in the name used for this species; see Hall, 1981:805. Ognev's arguments for ratticeps are convincing, but would require nomenclatural reorganization in two subgenera. This problem might be best submitted to the ICZN for resolution (SRL).

ISIS NUMBER: 5301410008080032001.