Niviventer fraternus (Robinson and Kloss 1916)

[Niviventer] fraternus (Robinson and Kloss 1916), J. Str. Br. Roy. Asiat. Soc., 73: 373.

Type Locality: Indonesia, W Sumatra, Korinchi Peak, 4700 ft (1432 m).

Vernacular Names: Montane Sumatran Niviventer.

Synonyms: Niviventer atchinensis (Sody 1941) .

Distribution: Montane forest formations along mountainous backbone of W Sumatra.

Discussion: Originally described as Epimys fraternus, but subsequently treated as a subspecies of Rattus rapit (Chasen, 1940), R. orbus (Ellerman, 1941), or Niviventer rapit (= Chasen’s R. rapit; Musser, 1970 b; Corbet and Hill, 1992); the latter authorities also included the Bornean rapit and Malay Peninsula cameroni as subspecies. Niviventer fraternus is about same size or larger than N. rapit, but smaller in body size than N. cameroni, without a tufted tail, and has a wider zygomatic plate than either N. cameroni or N. rapit . Multivariate analyses of morphometric traits cluster N. fraternus tightly with N. fulvescens and its allies and not with either N. cameroni or N. rapit (Musser and Lunde, ms). Member of a murine cluster endemic to Sumatra (Musser, 1986; also see account of Maxomys hylomyoides).