648.

Soft-furred Taiwan White-bellied Rat

Niviventer culturatus

French: Rat de Taiwan / German: Taiwan-WeiRRbauchratte / Spanish: Rata de vientre blanco de pelaje suave de Taiwan

Other common names: Formosan White-bellied Rat, Oldfield White-bellied Rat, Soft-furred Taiwan Niviventer, Taiwan Niviventer

Taxonomy. Rattus culturatus Thomas, 1917,

“Mt. Arizan, Formosa [= Thailand]. Alt. 8000 ft [= 2440 m].”

Niviventer culturatus was considered a subspecies of N. confucianus but was split from it based on morphological data and later phylogenetic data; however, its phylogenetic position is still obscure. Monotypic.

Distribution. SC Taiwan.

Descriptive notes. Head-body 130- 150 mm, tail 170-200 mm, ear 23- 25 mm, hindfoot 99_35 mm; weight 86-213 g (males) and 62-119 g (females). The Soft-furred Taiwan White-bellied Rat is medium-sized, with soft pelage and no spines or guard hairs. Males are significantly larger than females. Dorsum is grayish brown and sharply demarcated from venter. Face is grayer than rest of body, and there is dark spot in front of and behind eyes. Venter is creamy white, lacking dark brown or chestnut patch on chest or neck. Tail is ¢.132% of head-body length and sharply bicolored, brown above and creamy white below; brown on top eventually tapers off, leaving tip of tail white. Ears are dark brown; vibrissae are long. Brown stripe on feet ends right before white toes. There are five digits on each foot, with fifth digit reduced with small claw. Skull is elongated and narrow, similar to that of the Confucian White-bellied Rat ( N. confucianus). Mites (Laelaps) and fleas (Neopsylla) have been recorded on Soft-furred Taiwan White-bellied Rats. There are four pairs of mammae: one pectoral, one post-axillary, one abdominal, and one inguinal. Chromosomal complement is 2n = 46, FN = 52.

Habitat. Highland primary hemlock forests, usually associated with large logs on forest floor, at elevations of 2000-3000 m. The Soft-furred Taiwan White-bellied Rat can be found in secondary habitat and has been found in monocultures of Cryptomeria (Cupressaceae) .

Food and Feeding. The Soft-furred Taiwan White-bellied Rat is probably semi-omniv-OTous.

Breeding. The Soft-furred Taiwan White-bellied Rat is capable of breeding year-round. Number of embryos ranges from two to four.

Activity patterns. The Soft-furred Taiwan White-bellied Rat is mostly terrestrial and nocturnal and prefers denning in large logs.

Movements, Home range and Social organization. Soft-furred Taiwan White-bellied Rats used understories in a Cryptomeria forest more than any other microhabitat. They avoid competition with Spiny Taiwan White-bellied Rats ( N. coninga) by occupying higher elevations.

Status and Conservation. Classified as Near Threatened on The IUCN Red List and classified as least concern on China’s Regional Red List. The Soft-furred Taiwan Whitebellied Rat has a restricted distribution (less than 5000 m*) and might be harmed by habitat degradation. It has been recorded in Yushan National Park and may occur in other protected areas.

Bibliography. Adler (1996), Hsu Fuhsiung et al. (2000), Jameson (1965), Jameson & Hsieh (1971), Li Yuchun et al. (2008), Lin Liangkong & Shiraishi (1992a), Lu Liang et al. (2015), Musser (1981a), Musser & Carleton (2005), Smith & Johnston (2008g), Smith & Yan Xie (2008), Yu Hontsen (1993, 1994), Yu Hontsen et al. (1996).