Niviventer fulvescens (Gray 1847)

[Niviventer] fulvescens (Gray 1847), Cat. Hodgson Coll. Brit. Mus .: 18.

Type Locality: Nepal.

Vernacular Names: Indomalayan Niviventer.

Synonyms: Niviventer baturus (Sody 1932); Niviventer besuki (Sody 1931); Niviventer blythi (Kloss 1917); Niviventer bukit (Bonhote 1903); Niviventer caudatior (Hodgson 1849); Niviventer cinnamomeus (Blyth 1859); Niviventer condorensis (Kloss 1926); Niviventer flavipilis (Shih 1930); Niviventer gracilis (Miller 1913); Niviventer huang (Bonhote 1905); Niviventer jacobsoni (Bartels 1937); Niviventer jerdoni (Blyth 1863); Niviventer lepidus (Miller 1913); Niviventer lepturoides (Sody 1934); Niviventer lieftincki (Chasen 1939); Niviventer ling (Bonhote 1905); Niviventer marinus (Kloss 1916); Niviventer mekongis (Robinson and Kloss 1922); Niviventer minor (Shih 1930); Niviventer octomammis (Gray 1863); Niviventer orbus (Robinson and Kloss 1914); Niviventer temmincki (Kloss 1921); Niviventer treubii (Robinson and Kiloss 1919); Niviventer vulpicolor (G. M. Allen 1926); Niviventer wongi (Shih 1931) .

Distribution: From S Himalayas (Nepal and N India; see Agrawal, 2000, for Indian distribution; Corbet and Hill, 1992 extend range to N Pakistan, but we have not seen any specimens from that region) through Bangladesh, S China (Wang, 2003; including Hainan Isl and Hong Kong), and Indochina (including Con Son Isl and several other islands off coast of Vietnam; Kuznetsov, 2000; Musser and Lunde, ms) to the Sunda Shelf on Peninsular Thailand (and offshore Koh Chang), Malay Peninsula (and offshore Koh Samui), Sumatra, Java, and Bali; absent from Borneo and other islands on the Sunda Shelf. Because samples of N. fulvescens have been confused with those of N. confucianus, N. niviventer, and N. tenaster in museum collections and the literature, the range outlined here derives primarily from Musser’s identification of specimens in AMNH, ANSP, BMNH, FMNH, HUNHM, MCZ, MNHN, MZB, RMBR, RMNH, USNM, and ZFMK.

Conservation: IUCN – Lower Risk (lc).

Discussion: Some authors have referred to populations on Bali, Java, Sumatra, Malay Peninsula, and peninsular Thailand as either N. rapit (Chasen, 1940) or N. bukit (Corbet and Hill, 1992; J. T. Marshall, Jr., 1977 a; Musser, 1981 b), and those occurring north of the Isthmus of Kra as N. fulvescens, pending taxonomic revision of the group. Abe’s (1983) study, which focused on Thai samples, and recent morphometric analyses combining Indochinese and Sundaic samples (Musser and Lunde, ms) support the hypothesis that specimens of bukit represent N. fulvescens (Abe, 1983), an arrangement reflecting the earlier view of Ellerman (1941) and particularly Osgood (1932:305): "The relationship of fulvescens to southern forms is obvious in several instances, especially in that of R. f. bukit which can at most be no more than a subspecies." This hypothesis will require additional testing with other data sets, including DNA sequences. The morphometric study by Musser and Lunde (ms) also demonstrates that N. fulvescens is part of a tight cluster containing the Thai endemic N. hinpoon, and the Sumatran N. fraternus, another phylogenetic pattern that will have to be tested by analyses of other kinds of morphological traits and gene sequences. Analysis of mtDNA cytochrome b sequences indicateed N. fulvescens to be phyletically closer to a monophyletic clade containing N. tenaster, N. coninga, N. confucianus, and N. culturatus than is N. langbianis (J. L. Patton, in litt., 2000; no other Niviventer were sampled). Neithammer and Martens (1975) regarded fulvescens to be only a color morph of N. niviventer in Nepal, but the two species are readily distinguished by pelage coloration and external, cranial, and dental dimensions (Abe, 1977; Musser and Lunde, ms).

If Indochinese and Sundaic populations all represent N. fulvescens, then that species is the only member of the genus with a geographic distribution encompassing the Indochinese mainland and some islands on the Sunda Shelf; other murines with roughly equivalent ranges are Berylmys bowersii, Chiropodomys gliroides, Leopoldamys sabanus, and Maxomys surifer (Musser and Newcomb, 1983; but see accounts of L. sabanus and M. surifer). Spermatozoal morphology of Malay Peninsula sample described by Breed and Yong (1986, as bukit) in comparative context. Chromosomal data for samples from Vietnam, Thailand, Malaya, Java, and Hong Kong summarized by Baskevich and Kuznetsov (2000). Biology, habitat, morphological variation, and taxonomy described by Abe (1971, 1977) for samples from C Nepal. Ecological relationships with N. confucianus and other murines in S Yunnan reported by Wu et al. (1996). Vietnamese records and other information provided by Dang et al. (1994), Kuznetsov (2000) and Lunde et al. (2003 b). Fossils identified as N. fulvescens were recovered from late Pleistocene cave sediments in the Sichuan-Guizhou region of S China (Zheng, 1993).