175.

Mount Isarog Hairy-tailed Rat

Batomys uragon

French: Batomys de | 'lsarog / German: Mount-Isarog-Haarschwanzratte / Spanish: Rata de cola peluda de | sarog

Taxonomy. Batomys uragon Balete et al., 2015,

Mt. Isarog, Camarines Sur Province, Luzon Island, Philippines .

Original specimens thought to belong to B. grantui. Separated on the basis of morpho-metric and molecular analyses, which indicate, nevertheless, that the two are indeed closely related. The cytochrome-b tree is relatively poorly supported and further analyses are needed to improve understanding of the evolution of the genus. The karyotype was established by E. A. Rickart and G. G. Musser in 1993,for specimens from Mount Isarog (under the name B. grantii) and were found to be similar to those of B. salomonseni . Monotypic.

Distribution. Known only from Mt Isarog, Luzon I, Philippines.

Descriptive notes. Head-body 177-206 mm, tail 128-171 mm, ear 20-22 mm, hindfoot 36-40 mm; weight 135-200 g. The Mount Isarog Hairy-tailed Rat is a medium-sized rat most similar to the Luzon Cordillera Hairy-tailed Rat ( B. grantii), but with a noticeably shorter tail. Dorsal pelage is medium to pale golden brown and relatively long. Ventral pelage is grayish buff with patches of unpigmented fur on the chin, pectoral, and inguinal

regions and is not sharply demarcated from dorsal pelage. A single male specimen had a small pale brown patch on the left side of the lower abdomen. Ears are relatively short compared to those of the Luzon Cordillera Hairy-tailed Rat, and are pale brown with short grayish brown hairs. There is a pale ring of skin surrounding the eyes that is covered with very short grayish brown and unpigmented hairs. Vibrissae are long. Feet have a dark brown mid-dorsalstripe, which is bordered by short, pale golden brown fur on each side. Claws are opaque with ungual tufts of unpigmented hairs. Palmar surface of both foreand hind feet are unpigmented. Hindfeet are broad and long while forefeet are broad; hindfeet have six large fleshy plantar pads. Tail is shorter (68-73%) than head-body length and is hairy and a dark brownish color. Compared to the Luzon Cordillera Hairy-tailed Rat, the Mount Isarog Hairy-tailed Rat has a smaller tail and ears, shorter nasals and incisive foramina, a narrower interorbital constriction, and broader incisors. Females bear two pairs of mammae, both inguinal. Karyotype is 2n = 52, FN =the Luzon Cordillera Hairy-tailed Rat52.

Habitat. Primary montane and mossy forest at elevations of 1350-1800 m.

Food and Feeding. Mount Isarog Hairy-tailed Rats are herbivorous, probably being granivorousfrugivorous. Their diet includes almost exclusively seeds and perhaps leaves and fruit. Stomach content of some individuals included masticated plant matter and a captive individual accepted seeds and sprouting dicots (eating only the seed while discarding the sprout), but rejected earthworms, insects, and many other plant materials including various small fruits, orchid bulbs, dried beans, and several types of leaves among others. Anothercaptive animals accepted small fruit and fried coconut covered in peanut butter.

Breeding. Two adult females with perforated vaginas, old placental scars, and enlarged mammae with 3—4 scars were captured in April, although the number oflitters this represents is unknown.

Activity patterns. The Mount Isarog Hairy-tailed Rat is nocturnal. It forages on the ground on well defined runways and among root tangles, butis also a good climber.

Movements, Home range and Social organization. A female had a home range of at least 0-1 ha; a densityof about 3 ind/ha was recorded at Mount Isarog, at 1700 m.

Status and Conservation. Not assessed on The IUCN Red List. The Mount Isarog Hairytailed Rat has a very limited distribution and further research is needed to determine the full distributional limits of this species as well as its potential conservation threats.

Bibliography. Balete et al. (2015), Heaney, Balete & Rickart (2016), Heaney, Balete, Rickart, Utzurrum & Gonzales (1999), Musser, Heaney & Tabaranza (1998), Rickart & Musser (1993), Rickart et al. (1991).