Clethrionomys sikotanensis (Tokuda, 1935) . Mem. Coll. Sci. Kyoto Imp. Univ., ser. B, 10:241.

TYPE LOCALITY: Russia, Kuril Islands, Sikotan Island .

DISTRIBUTION: Islands of Sikotan, Daikoku, and Rishiri (Imaizumi, 1971); limits of insular distribution unresolved.

SYNONYMS: microtinus .

COMMENTS: Allocated by Corbet (1978c) and Aimi (1980) to C. rufocanus but recognized as a distinct species by Gromov and Polyakov (1977), Imaizumi (1971, 1972), and Pavlinov and Rossolimo (1987). The status of microtinus was discussed by Gromov and Polyakov (1977) and Pavlinov and Rossolimo (1987).