736.

Daovantien’s Limestone Rat

Tonkinomys daovantieni

French: Rat de Dao Van Tien / German: Daovantien-Karstratte / Spanish: Rata de caliza de Daovantien

Taxonomy. Tonkinomys daovantieni Musser, Lunde & Nguyen Truong Son, 2006,

*in the vicinity of Lan; Dat Village (21°40°52"

W/106°20°28”E), 150 m, Huu Lién Nature Reserve, Huu Lién Commune, HuulLLung District, Lang Son Province, Vietnam.”

This species is monotypic.

Distribution. Known only from Huu Lién Nature Reserve in N Vietnam.

Descriptive notes. Head-body 184- 217 mm, tail 156-183 mm, ear 29-31 mm, hindfoot 37-41 mm; weight 140-205 g. Daovantien’s Limestone Rat has semi-spinous grayish black fur, white patch on head, dark gray underpart with white patch on chest, and grayish rhinarium, lips, and ears. Chin is unpigmented. Characteristic elongated superciliary and mystacial vibrissae adorn head. Forefeet are whitish dorsally; hindfeet are white, with brownish metatarsal region. Tail is shorter than head-body length, with unpigmented part on its one-fourth distal end. There are four pairs of mammae: one post-axillary, one abdominal, and two inguinal. Skull is robust, with wide and slightly elongated rostrum. Temporal and postorbital ridges are well-developed. Occiput is deep, and zygomatic arch is robust. Occiput is deep, especially laterally. Squamosal root of zygomatic arch is placed high on tympanic bulla. There are no large subsquamosal foramen or narrow alisphenoid strut. Incisive foramen are slightly elongated and wide, with their posterior margin not reaching orslightly reaching anterior border of M'. Palatal bridge is wide and long, expanding posteriorly well beyond M?®. Cheek teeth rows are posteriorly divergent. Sphenopalatine vacuities are small, with wide pterygoid and mesopterygoid fossa. Tympanic bullae are small relative to skull length and do not completely cover carotid canal area. There is large foramen for the stapedial artery but no sphenofrontal foramen or squamoso-alisphenoid groove. Jaw has short coronoid process. Angular and condyloid processes make obtuse angle where theyjoin. Upper incisors are opisthodont. There are four upper molar roots for M', three for M?, and three for M”. Two upper molar roots for M, two for M,, and two for M,. Cheek teeth are brachydont, with simplified occlusal cusp patterns.

Habitat. Karst forest habitats mainly on talus of limestone blocks in lowland forest.

Food and Feeding. Daovantien’s Limestone Rat is omnivorous and eats insects.

Breeding. No information.

Activity patterns. Daovantien’s Limestone Rat is mostly nocturnal, but some specimens were caught during the day.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Data Deficient on The IUCN Red List. Daovantien’s Limestone Rat might be not become threatened as long as karst forest habitats are protected from human activities. It might occur in suitable karstic habitats beyond its known distribution in Vietnam.

Bibliography. Balakirev, Abramov & Rozhnov (2013), Latinne et al. (2011b), Musseret al. (2006), Pagés et al. (2016).