Niviventer fulvescens (Smith & Xie, 2008)

Ge, Deyan, Feijó, Anderson, Abramov, Alexei V., Wen, Zhixin, Liu, Zhengjia, Cheng, Jilong, Xia, Lin, Lu, Liang & Yang, Qisen, 2021, Molecular phylogeny and morphological diversity of the Niviventer fulvescens species complex with emphasis on species from China, Zoological Journal of the Linnean Society 191 : -

NIVIVENTER FULVESCENS (GRAY, 1847)

( FIGS 5B, 6)

Indomalayan niviventer, chestnut white-bellied rat.

Mus fulvescens Grey, 1847: 18 . Nepal.

Mus caudatior Hodgson, 1849: 203 . Nepal.

Holotype: NHM 45.1.8.376. Collected by B. H. Hodgson. The holotype is badly damaged. The animal

is small and immature, with the dorsal and ventral coat missing in several places.

Type locality: Nepal.

Measurements: No measurements were available for the holotype. BM, EMs and CMs (mean ± 1 SD, range, BM in g, measurements in mm) from molecular vouchers and museum specimens: BM = 66.82 ± 14.04 (40–91, N = 37). EMs of 37 adult specimens: HBL = 131.60 ± 11.18, TL = 187.74 ± 14.94, HFL = 27.22 ± 2.01 and EL = 20 ± 2.50. CMs from 29 intact adult specimens: TLC = 15.15 ± 1.73, NL = 12.92 ± 1.22, GWS = 5.40 ± 0.44, SDO = 5.65 ± 0.30, ZB = 15.09 ± 1.24, GMB = 13.28 ± 0.61, PL = 17.27 ± 0.95, IFL = 5.79 ± 0.59, WIF = 2.52 ± 0.20, GPB = 6.68 ± 0.35, LTB = 5.84 ± 0.52, ULMM = 5.76 ± 0.30, ULMD = 8.86 ± 0.68, ML = 16.70 ± 1.13, LLMM = 5.66 ± 0.33 and LLMD = 4.61 ± 0.49.

Diagnosis: Niviventer fulvescens can be distinguished from other species within the NFSC by its longer tail and ears. It could be easily mistaken for N. huang , but N. fulvescens inhabits higher elevations.

Distribution: Nepal, south-western China and northern Indochina. In China it is distributed in higher mountains from south-western Yunnan to south-eastern Tibet.

Comments: Niviventer fulvescens is taxonomically the most ambiguous species of the NFSC. Previous studies largely overestimated the distribution range of this species ( Allen, 1938; Musser & Carleton, 2005). According to molecular voucher specimens, it inhabits middle- to high-elevation mountains in south-western Yunnan and south-eastern Tibet. The present analyses identifies two major genetic lineages within N. fulvescens ( Fig. 1); the first lineage was confined to south-eastern Tibet along the Himalayan Mountains. The second lineage was distributed in south-western Yunnan, western Sichuan and northern Vietnam. Pelage coloration differs slightly between these two genetic lineages. The lineage from south-eastern Tibet has a darker coloration than those from Yunnan. Spines are more prominent in individuals from Yunnan than in those from the other locations.

Sympatric species: The distribution of N. fulvescens largely overlaps with those of N. andersoni and N. niviventer . The last two species also inhabit middleto high-elevation mountains in southern China. Niviventer andersoni is distinguishable by its larger size and bicoloured tail (the one-third near the tip is white) and N. niviventer belongs to the NNSC and has a darker pelage.