Microtus umbrosus (Merriam, 1898)

Don E. Wilson, Russell A. Mittermeier & Thomas E. Lacher, Jr, 2017, Cricetidae, Handbook of the Mammals of the World – Volume 7 Rodents II, Barcelona: Lynx Edicions, pp. 204-535 : 335

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).

Figures

On following pages: 115. Reed Vole (Alexandromys fortis); 116. Sakhalin Vole (Alexandromys sachalinensis); 117. Mongolian Vole (Alexandromys mongolicus); 118. Middendorff's Vole (Alexandromys middendorffii; 119. Gromov's Vole (Alexandromys gromovi); 120. Lacustrine Vole (Alexandromys limnophilus); 121. Root Vole (Alexandromys oeconomus); 122. Taiwan Vole (Alexandromys kikuchii); 123. Japanese Grass Vole (Alexandromys montebell); 124. Afghan Vole (Microtus afghanus); 125. Bucharian Vole (Microtus bucharensis); 126. Juniper Vole (Microtus juldaschi); 127. Short-tailed Field Vole (Microtus agrestis); 128. Mediterranean Field Vole (Microtus lavernedii): 129. Portuguese Field Vole (Microtus rozianus); 130. Insular Vole (Microtus abbreviatus); 131. Singing Vole (Microtus miurus); 132. Rock Vole (Microtus chrotorrhinus); 133. Zempoaltepec Vole (Microtus umbrosus); 134. Tarabundi Vole (Microtus oaxacensis); 135. Guatemalan Vole (Microtus guatemalensis); 136. Woodland Vole (Microtus pinetorum); 137. Jalapan Vole (Microtus quasiater); 138. California Vole (Microtus californicus): 139. Beach Vole (Microtus brewer); 140. Mexican Vole (Microtus mexicanus); 141. Mogollon Vole (Microtus mogollonensis); 142. Prairie Vole (Microtus ochrogasten; 143. Taiga Vole (Microtus xanthognathus); 144. Cabrera'’s Vole (Microtus cabrerae); 145. North American Water Vole (Microtus richardson); 146. Gray-tailed Vole (Microtus canicaudus).

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