Microtus townsendii
| Townsend's Vole
(Microtus townsendii) | |
|---|---|
| Range | |
 | |
| Taxonomic classification | |
| Order: | Rodentia |
| Suborder: | Supramyomorpha |
| Infraorder: | Myomorphi |
| Superfamily: | Muroidea |
| Family: | Cricetidae |
| Subfamily: | Arvicolinae |
| Tribe: | Arvicolini |
| Genus: | Microtus |
| Subgenus: | Mynomes |
| Binomial details | |
| Microtus townsendii (Bachman, 1839) | |
| Other resources | |
| Full taxonomic details at MDD | |
The Townsend's Vole (Microtus townsendii) is a large, dark brown vole found in the northwestern United States and parts of southern British Columbia, including Vancouver Island. It is generally found in mesic habitats with suitable cover.
Description
From Cornely & Verts (1998): "Microtus townsendii is a large dark-brownish vole with large broad ears that extend above the fur; tail long, usually blackish or brownish; feet brownish or blackish with brown claws (Bachman, 1839; Bailey, 1900)."
External measurements
Length measurements are in millimeters (mm) and weight measurements are in grams (g), unless stated otherwise. If available, the sample size (n=) is provided. If a range is not provided and n= is not given, then the listed measurement represents an average.
| Part of range | Reference | Total length | Tail length | Hindfoot length | Ear length | Mass |
|---|---|---|---|---|---|---|
| California | Jameson & Peeters (2004) | 169–222 | 48–70 | 20–26 | 15–17 | 75–82 |
| Canada | Naughton (2012) | 155–235 | 42–75 | 19–29 | 10–18 | 40–103 |
| not reported | Hall (1981) and Hall & Cockrum (1953); compiled by Cornely & Verts (1988) | 169–225 | 48–70 | 20–26 | 15–17 | 47–82.5 (Maser and Storm, 1970) |
| Oregon | Verts & Carraway (1998) | females: 151–220 (n=30); males: 162–226 (n=30) | females: 38–62 (n=30); males: 42–84 (n=30) | females: 22–28 (n=30); males: 15–36 (n=30) | females: 37.2–70.7 (n=30); males: 33.0–82.0 (n=30) |
Skull
From Verts & Carraway (1998): "The skull is robust and angular, with heavy ridges; the incisive foramina are long, narrow, and constricted posteriorly."
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Holotype: USNM 10083/4157. Microtus townsendii townsendii. Age and sex unknown. Puget Sound, Oregon (Washington). Collection date unknown, but on or before 1860. Dorsal view of the skull. -
Holotype: USNM 10083/4157. Microtus townsendii townsendii. Age and sex unknown. Puget Sound, Oregon (Washington). Collection date unknown, but on or before 1860. Ventral view of the skull. -
Holotype: USNM 10083/4157. Microtus townsendii townsendii. Age and sex unknown. Puget Sound, Oregon (Washington). Collection date unknown, but on or before 1860. Lateral view of the skull. -
Holotype: USNM 10083/4157. Microtus townsendii townsendii. Age and sex unknown. Puget Sound, Oregon (Washington). Collection date unknown, but on or before 1860. Dorsal view of the mandible. -
Holotype: USNM 10083/4157. Microtus townsendii townsendii. Age and sex unknown. Puget Sound, Oregon (Washington). Collection date unknown, but on or before 1860. Lateral view of the left mandible.
Similar species
From Cornely & Verts (1988): "Microtus townsendii can be distinguished from sympatric congeners by the following characters: from M. oregoni by eye >4 mm in diameter, four loops of enamel on lingual side of M3, and a longer tail; from M. canicaudus by nearly uniformly blackish or dark-brownish tail, U-shaped margin of palate, and incisive foramina >6 mm long; from M. richardsoni by six plantar tubercles, incisive foramina not forming narrow slits posteriorly, and incisors not greatly procumbent; from M. californicus by nearly uniformly blackish or dark-brownish tail, incisive foramina widest in the anterior half, and incisors not entirely obscured by nasals in dorsal view; from M. longicaudus by nearly uniformly blackish or dark-brownish tail, tail <50% of head and body length, and incisors not entirely obscured by nasals in dorsal view; from [Microtus drummondii] by M2 with four loop of enamel and tail >30% of head and body length. Distinguishing characteristics were adapted from Dalquest (1948), Hall (1981), Ingles (1965), and Verts and Carraway (1984)."
References
Bachman J. 1839. Description of several new species of American quadrupeds. J. Acad. Sci., Philadelphia, 8:57-7.
Cornely JE, Verts BJ. 1988. Microtus townsendii. Mammalian Species (325): 1-9. https://doi.org/10.2307/3504129
Dalquest WW. 1948. Mammals of Washington. Univ. Kansas Publ., Mus. Nat. Hist., 2:1-444.
Hall ER. 1981. The mammals of North America. Second edition. John Wiley & Sons, New York.
Ingles LG. 1965. Mammals of the Pacific states: California, Oregon, and Washington. Stanford Univ. Press, Stanford, California, 506.
Verts BJ, Carraway LN. 1984. Keys to the mammals of Oregon. Third ed. O.S.U. Book Stores, Inc., Corvallis, Oregon, 178 pp.
Verts BJ, Carraway LN. 1998. Land mammals of Oregon. Berkeley (CA, USA): University of California Press.