The Zempoaltépec vole (Microtus umbrosus ) is a species of rodent in the family Cricetidae. The name Microtus is from the Greek word mikros meaning small and otus meaning ear. The name umbrosus could be from the Latin umbros meaning shady. It is rather large and has a long tail when compared with other voles. Its pelage is long and soft. In the upper parts, the hair is uniformly dusky with brown tips and the lower parts a dark grey thinly washed with a reddish yellow color. It is found only in Mexico, in a semi-isolated mountain range southeast of the Cajones River in Mixes district, in Oaxaca.
Microtus umbrosus is limited to a semi-isolated mountain range southeast of the Cajones River in the Mixes district of Oaxaca, Mexico. The species has been recorded in an altitude ranging from 1,829 meters in the town of Totontepec to 2,499-3,000 meters on Mount Zempoaltépec at the southern end of the mountain range.
The habitat of this species can be described as humid Upper Astral Zone, dense oak forest, montane pine-oak forest, evergreen cloud-forest, and evergreen broadleaf rainforest. It has been reported from the humid Upper Tropic Subzone. It lives in borrows and long tunnels in moderately moist, well-drained soil.
The Zempoaltépec vole is considered an endangered and fragile species. This is due to its very restricted geographic range and habitat modification in the state of Oaxaca. Unfortunately, the species lives in an unprotected area. In order to improve conservation efforts in Mexico, additional reserves including the area of M. umbrosus, should be added to additional reserves. Priority for this particular area should be considered as it is home to eight other species of interest.
