Rattus koopmani Musser and Holden, 1991 . Bull. Am. Mus. Nat. Hist., 206:389.

TYPE LOCALITY: Indonesia, Kepulauan Banggai, Pulau Peleng (1 °23'S, 123°14'E), which is separated from mainland Sulawesi by deepwater Selat Peleng .

DISTRIBUTION: Known only from Peleng Isl.

COMMENTS: Represented only by the holotype. In some characters, R. koopmani resembles the Sulawesian R. hoffmanni, but it also shares other traits with R. elaphinus from Taliabu Isl to the east of Peleng Isl. More specimens are needed to assess morphological variation (Musser and Holden, 1991) and better estimate phylogenetic affinity.