6H4.

Indochinese Mountain White-bellied Rat

Niviventer tenaster

French: Rat du Mulayit / German: Indochinesische Weiftbauchratte / Spanish: Rata de vientre blanco de Indochina

Other common names: Indochinese Mountain Niviventer, Tenasserim White-bellied Rat

Taxonomy. Epimys tenaster Thomas, 1916,

“Mount Muleyit, Tenasserim [Kayin State, southern Burma]. Alt. 5000-6000" [= 1525-1830 m].”

Niviventer tenaster is morphologically most similar to N. confucianus, but phylogenetic relationships are unresolved, and further genetic and morphological studies are needed to determine its placement within Niviventer . Recently, the Hainan populaLion was split into its own species, N. lotipes,

based on karyological data and later validated by phylogenetic data, although morphological studies are needed to further validate this view. Monotypic.

Distribution. WC & S Myanmar, NW Thailand (Chiang Mai Province), Laos, Vietnam, and S Cambodia (Damrei Mts).

Descriptive notes. Head-body 120-190 mm, tail 175-235 mm, ear 23-26 mm, hindfoot 32-35 mm; weight 50-140 g. The Indochinese Mountain White-bellied Ratis larger than all other species of Niviventer except the Confucian White-bellied Rat ( N. confucianus), which it is very similar to, and the Spiny Taiwan White-bellied Rat ( N. coninga), which might be larger. Pelage is soft, covered with dark brown sturdy but flexible spines. Dorsum is dark brown, with lighter but prominent ruby reddish side—lighter than the Indochinese White-bellied Rat ( N. fulvescens) and without chocolate brown hue of the Confucian White-bellied Rat and spinier than the Bukit White-bellied Rat ( N. bukit). Top offeet of the Indochinese Mountain White-bellied Rat have dark brown or chestnut stripe that stops just before white toes. Dorsum and venter are sharply demarcated. Venter is pure white, without any chest or chin markings.Tail is ¢.151% of head-body length and sharply bicolored, dark brown above and paler below, although dark top can fade toward tip in some specimens, although it is never completely unicolored as inthe Himalayan White-bellied Rat ( N. niviventer). There are five digits on each foot, with fifth digit reduced with small claw. Skull is large, exceeding 41 mm, but lightly built and elongated. There are four pairs of mammae: one pectoral, one post-axillary, one abdominal, and one inguinal. Chromosomal complement is 2n = 46, FN = 54.

Habitat. Montane rainforests at elevations of 1300-3000 mFood and Feeding. No information.

Breeding. No information.

Activity patterns. The Indochinese Mountain White-bellied Rat is nocturnal and mostly terrestrial. It travels across vines and has been captured on woody lianas threading through dense stands of bamboo. It was also caught at primary forest on the ground and 1-2 m aboveground (on trees and lianas) on the Dalat Plateau in southern Vietnam.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List (including N. lotipes). The Indochinese Mountain White-bellied Ratis not reported as abundant anywhere but is represented by large collections of specimens.

Bibliography. Abramov et al. (2010), Aplin (2016g), Balakirev & Rozhnov (2010), Balakirev et al. (2011), He Kai & Jiang Xuelong (2015), Jing Meidong et al. (2007), Li Yuchun et al. (2008), Lu Liang et al. (2015), Lunde et al. (2003), Musser (1973b, 1981a), Musser & Carleton (2005), Smith & Yan Xie (2008).