Microtus umbrosus
| Zempoaltépec vole | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Rodentia |
| Family: | Cricetidae |
| Genus: | Microtus |
| Species: | M. umbrosus |
| Binomial name | |
|
Microtus umbrosus Merriam, 1898 |
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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 subterranean tunnels in moderately moist, well-drained soil.
There exists many anatomical features unique to the Zempoaltépec vole in characterizing the species. This species is larger, has a much longer tail, and large hind feet compared with its other Mexican vole counterparts. Its tail is roughly 33% of its total body length, longer than most other species from the same genus. The feet are large with five plantar tubercles and a basic sixth tubercle. The presence of two pairs mammary glands in the groin area and the absence of mammary glands in the pectoral area is a key feature for this species.
Total dentition of this species is 4 incisors, no canines or premolars, and 12 molars totaling 16 teeth. On the last mandibular molar there is the presence of two transverse loops and at least one closed median triangle rather than none. The closed median triangle can be found in other North American Microtus species such as M. oaxacensis and M. guatamalensis. The Zempoaltépec vole can be further distinguished by two triangles on the last maxillary molar rather than five that exist in M. oaxacensis or three in M. guatamalensis. The first mandibular molar has an anterior cap merging with two open triangles, three closed triangles, and a posterior lobe.
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Wikipedia