133.

Zempoaltepec Vole

Microtus umbrosus

French: Campagnol du Zempoaltepec / German: Zempoaltepec-Wihlimaus / Spanish: Topillo de Zempoaltépetl

Taxonomy. Microtus umbrosus Merriam, 1898, Mt. Zempoaltépec, 8200 ft. (= 2500 m), Oaxaca, Mexico.

Microtus umbrosus is not closely related to other Mexican or Central American voles, suggesting ancient and independent ancestral colonization of the region. Monotypic.

Distribution. Restricted to Cerro Zempoaltépec slopes in NC Oaxaca, Mexico.

Descriptive notes. Head-body 115-133 mm, tail 49-65 mm, ear 14-16 mm, hindfoot 22-24 mm; weight 42 g. Dorsal pelage of the medium-sized Zempoaltepec Vole is long and dark; venter is dark plumbeous. Tail is relatively long, bicolored, and sparsely haired; feet are large and dark brown. There are five plantar tubercles on feet, two inguinal mammae, and no pectoral mammae; these features are diagnostic for the Zempoaltepec Vole. Skull is elongate and narrow and has small bullae. M” has two closed triangles, and last M, has two transverse loops. Chromosomal complement is 2n = 56, FN = 60.

Habitat. Meadows or cleared pastures in humid oak ( Quercus, Fagaceae) forests, mixed pine-oak forests, evergreen cloud-forest, and evergreen broadleaf rainforest at elevations of 1800-3000 m.

Food and Feeding. The Zempoaltepec Vole likely eats grasses and forbs.

Breeding. No information.

Activity patterns. The Zempoaltepec Vole makes long underground tunnels and lives in burrows.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Endangered on The IUCN Red List. The Zempoaltepec Vole is estimated to occupy less than 500 km?, habitat is severely fragmented, and extent of occurrence and quality of habitat have declined in recent decades.

Bibliography. Bradley, Ammerman et al. (2014), Ceballos & Oliva (2006), Conroy & Cook (2000a), Conroy et al. (2001), Frey & Cervantes (1997a), de Grammont & Cuardn (2008b), Hall (1981), Musser & Carleton (2005).