195.

Mindanao Mossy Forest Mouse

Apomys hylocoetes

French: Apomys des mousses / German: Nebelwald-Philippinenwaldmaus / Spanish: Ratén de bosque de Mindanao

Other common names: Mindanao Apomys, Mount Apo Forest Mouse

Taxonomy. Apomys hylocoetes Mearns, 1905,

“Mount Apo at 6,000 feet altitude [= 1829 m], southern Mindanao, Philippine Islands.”

Original spelling hylocoetes is a latinized

Greek word and cannot be modified, so widely used specific epithet hylocetes has been changed. Apomys hylocoetes is type species of genus and subgenus. Molecular evidence suggests special affinity with A. insignis from Mindanao, A. caminguensis from (Camiguan, and an undescribed species from Bohol, Leyte, Samar, and Biliran. Specimens from 2286 m on Mount Apo have been described as a furtherspecies, A. petraeus, but differences are slight and very likely due to age and elevational differences; A. hylocoeles 1s sympatric with A. insignis at 1829 m on Mount Apo. Mitochondrial sequences do not distinguish A. hylocoetes from sympatric A. insignis from Mount Kitanglad Range, but this may be due to introgression or mitochondrial capture as the two species differ markedly in karyotype. Currently regarded as monotypic but in need of further assessment.

Distribution. Mindanao I, S Philippines, where recorded from several localities in Kitanglad Range at 1900-2800 m and from Mt Apo at 1829-2286 m;it probably occurs in the Kamangkil-Lumut Ranges that extend into L.anao del Sur Province.

Descriptive notes. Head-body 111-115 mm, tail 120-150 mm, ear 18-22 mm, hindfoot 29-34 mm; weight 33-45 g. Species of Apomys are soft-furred, small to medium-sized murines with relatively unspecialized body form; distinguished from other Philippine murines by distinctive suite of features, including long, narrow hindfeet, thinly furred tail, unreduced eyes,relatively large and thinly furred ears, vibrissae on snout very elongate and, folded back, reach to shoulder or beyond, reduction to two mammae on each side, both inguinal, and a simplified molar pattern with cusps united into transverse laminae. Members of subgenus Apomys are small, long-tailed species typically most active in canopy. The Mindanao Mossy Forest Apomys has fur on upperparts, flanks and outer surfaces of limbs dense and very soft, without spines or stiff hairs, dark brown without “saltand-pepper speckling”; fur on underparts and inside of limbs is “deep buffy gray”; colors of upperside and underside merge gradually on flanks; ears relatively longer than in sympatric A. insignis, darkly pigmented, and with short hairs on outer surface; eyes without any conspicuous emargination. Dark fur of limbs extends onto upper surfaces of foreand hindfeet, but digits are unpigmented and covered with shorter

white hairs; hindfeet relatively shorter and wider than in other members of subgenus Apomys, undersurface lightly pigmented, plantar pads small and well separated, hallucal pad short and positioned farther back than in other species of subgenus Apomys, digits moderately long and slender, with delicate and sharply pointed claws. Tail long (averaging c.130% of head-body length), clearly bicolored, brown above and pale gray below for nearly entire length, terminating in short white tip;tail scales conspicuous but relatively small, in 14-15 rows per cm near tail base, and usually with three short hairs per scale, hair length increasing toward tail tip but without terminal brush. Cranium is very similar to that of other members of subgenus Apomys, but braincase rounder and more inflated than in sympatric A. insignis . Chromosomal complement has 2n = 48 and FN = 56, autosomes include one pair of small submetacentric, three pairs of small subtelocentric, and 20 pairs of telocentric chromosomes graded large to small. Sex chromosomes not obvious, hence X and Y chromosomes presumably both telocentric.

Habitat. Forest inhabited by Mindanao Mossy Forest Mice is evergreen tropical rainforest of the kinds categorized by Philippine ecologists as “montane forest” and “mossy forest,” at elevations of ¢.1800-2800 m. The species occurs in areas of natural disturbance such as regeneration after landslides. Original captures of this species were made in primary forest and at higher elevation, among rocks above forest zone.

Food and Feeding. The Mindanao Mossy Forest Mouse is thought to be omnivorous.

Breeding. No information.

Activity patterns. No information.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List (as A. hylocetes). This species appears to be most common in primary mossy forest, where it is the most abundant murid species. It is less abundant at lower elevations in primary montane forest. Populations are present in three National Parks (Mount Kitanglad, Mount Apo, and Mount Kalatungan Range).

Bibliography. Heaney (2016b), Heaney, Balete et al. (1998), Heaney, Tabaranza, Rickart et al. (2006), Mearns (1905), Musser (1982a), Musser & Carleton (2005), Rickart & Heaney (2002).