726.

Thomas's Tree Rat

Chiromyscus thomasi

French: Rat de Thomas / German: Thomas-Fea-Baumratte / Spanish: Rata arboricola de Thomas

Other common names: Thomas's Masked Tree Rat

Taxonomy. Chiromyscus thomasi Balakirev, Abramov & Rozhnov, 2014,

“Vietnam, Son La Province, Muong Thai Village, near Lung Lo pass, 21°18'31"N, 104°41’3¢4°F, elevation ¢.450 m above sea level.”

Populations of C. thomas: were previously included in C. chiropus . Specimens from most of Indochina should be examined to determine if they are C. thomasi, C. chiro-pus, or C. langbianus. Monotypic.

Distribution. Reliably in N & C Vietnam (Lao Cai, Son La, Nhge An, and Kon Tum provinces) and N Laos (Xiangkhouang and [Luang Prabang provinces), but range limits still unknown.

Descriptive notes. Head-body 140-180 mm, tail 200-231 mm, ear 18-20 mm, hindfoot 27-29 mm. No specific data are available for body weight. Thomas's Tree Rat is the largest species of Chiromyscus and also the most striking. Pelage is dense, downy, and bright fulvous, with orange hue dorsally and brighter on sides. Cheeks, lateral surface of neck, front legs, rump, hips, and tail base are rich ocherous. Ven-ter is pure unblotched white, and line between dorsal and ventral pelage is abrupt. Black strip, or “mask,” surrounding eyes is most diagnostic. Claws are long and curved, although hallux has nail instead of claw. Feet and toes are usually white, with orange hair on top. Vibrissae are black and white and fairly long (60 mm). Ears are small, rounded, and pale brown. Tail is proximally tinged pale brown on top, little lighter on bottom with pinkish hue, and 128-132% of head-body length. Supraorbital ridge is more developed, and skull is more robust compared with other species of Chiromyscus .

Habitat. Tropical moist deciduous and evergreen forests.

Food and Feeding. No information.

Breeding. No information.

Activity patterns. Thomas's Tree Rat is nocturnal and arboreal.

Movements, Home range and Social organization. No information.

Status and Conservation. Not assessed on The IUCN Red List. Currently known distribution of Thomas’s Tree Rat is scattered, but its true limits are unknown. Research into its natural history and biogeography, especially given rarity of museum specimens, is needed.

Bibliography. Balakirev et al. (2014), Francis (2008).