Niviventer excelsior

643.

Sichuan White-bellied Rat

Niviventer excelsior

French: Rat du Sichuan / German: Sichuan-Weilbauchratte / Spanish: Rata de vientre blanco de Sichuan

Other common names: Large White-bellied Rat, Sichuan Niviventer

Taxonomy. Epimys excelsior Thomas, 1911,

Tatsienlu, 9000 ft (= 2744 m), western Sichuan, south-western China.

Recent phylogenetic work has placed N. excelsior sister to N. andersoni. Specimens allocated to N. excelsior variously cluster within N. andersoni, although this may be attributed to misidentification because the two species are very similar. More re-search is needed to determine their true phylogenies and distributions. There are two genetic clusters: one in Sichuan and another in Yunnan and south-eastern Tibet. The subspecies tengchongensis, originally mentioned in a checklist of the species and subspecies of China, might be valid based on skull morphology and limited genetic data, although it might be a nomen nudum. Monotypic.

Distribution. S China (SW Sichuan and NW & C Yunnan).

Descriptive notes. Head-body 127-175 mm, tail 190-213 mm, ear 22-27 mm, hind-foot 31-33 mm; weight 38-1-41-3 g. The Sichuan White-bellied Ratis large but smaller than Anderson’s White-bellied Rat (N. andersoni). Pelageis soft and short, silkier than Anderson’s White-bellied Rat, but it has flexible soft spines. Dorsum is dull grayish brown, with black hairs mixed throughout and brighter ocherous brown and less black on sides and cheeks. Dorsum and venter are demarcated sharply, and venter is pure white, extending to chin,lip, and ventral part of forelegs; some specimens have buffy spot on chest. Ears are dark brown; vibrissae are long. Tail is ¢.133% of head-body length and bicolored except at base, which is dark all around; it isbrownish black above and white or mottled below; and it has long hairs running its full length, ending with short white tuft at tip that is longer than that of Anderson’s White-bellied Rat. Skull is laterally convex, smaller, more gracile, and more slender than that of Anderson’s White-bellied Rat. Various species of gammasid mites have been recorded at high densities on the Sichuan White-bellied Rat. There are four pairs of mammae: one pectoral, one post-axillary, one abdominal, and one inguinal.

Habitat. High montane forests in elevations of 2300-3000 m.

Food and Feeding. The Sichuan White-bellied Rat probably eats seeds, other vegetation, and arthropods, similar to Anderson’s White-bellied Rat and the Sichuan Whitebellied Rat.

Breeding. No information.

Activity patterns. The Sichuan White-bellied Rat is arboreal and probably nocturnal.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Sichuan White-bellied Rat has a large distribution and probably large and stable overall population.

Bibliography. Balakirev & Rozhnov (2010), Chen Weicai, Liu Shaoying et al. (2010), Chen Weicai, Yue Bisong & Liu Shaoying (2010), Deng Xianyu et al. (2006), He Kai & Jiang Xuelong (2015), Huang Ligin et al. (2010), Jing Meidong et al. (2007), Lu Liang et al. (2015), Musser (1981a), Musser & Carleton (2005), Musser & Chiu (1979), Smith (2016d), Smith & Yan Xie (2008), Wang Yingxiang (2003), Zheng Shaohua (1993).