Arborimus longicaudus
Red Tree Vole
(Arborimus longicaudus) | |
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Range | |
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Taxonomic classification | |
Order: | Rodentia |
Suborder: | Supramyomorpha |
Infraorder: | Myomorphi |
Superfamily: | Muroidea |
Family: | Cricetidae |
Subfamily: | Arvicolinae |
Tribe: | Pliophenacomyini |
Genus: | Arborimus |
Binomial details | |
Arborimus longicaudus (F. W. True, 1890) |
Description
From Hayes (1996): "Arborimus longicaudus is a small (mass 25 to 50 g) microtine rodent. The dorsal pelage is uniformly cinnamon (Hall, 1981) or bright rusty brown (True, 1890) with many hairs tipped in black in A. l. longicaudus, but a light (sayal) brown sparsely tipped with black in A. l. silvicola (Hall, 1981; Howell, 1921; True, 1890); the underparts are whitish in both subspecies (Hall, 1981). The tail is long and well-haired, varying from black to brown and not distinctly bicolored (Maser and Storm, 1970). Juveniles are duller, with less red and more brown in dorsal coloration and black tails (Maser and Storm, 1970). Melanistic forms of A. l. silvicola can occur."
From Jameson & Peeters (2004), describing both Arborimus longicaudus and Arborimus pomo: "Bright chestnut red or brick red voles with a long, well-furred tail, curved claws, and ears partly concealed in fur. The species A. pomo and A. longicaudus have chromosomal differences but apparently cannot be separated in the field. Both might possibly be confused with the California Red-backed Vole (Clethrionomys californicus), which is much darker red and has a shorter tail."

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 |
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California | Jameson & Peeters (2004) | 158–186 | 60–76 | 19–21 | 10–11 | 24–27 |
rangewide except for northwestern portion of range | Hall (1981) | males: 193; females: 191 | males: 87; females: 81 | males: 20; females: 22 |
Skull
From Hayes (1996): "Skulls of the genus Arborimus can be separated from those of other arvicoline genera in the range of A. longicaudus by reentrant angles of the lower molars extending about two-thirds the way toward the labial side on the lingual side and about one-third the way toward the lingual side on the labial side. The skull of A. longicaudus can be distinguished from A. albipes by the combination of a pronounced longitudinal depression between the orbits that is bordered by a strong ridge, strongly recurved incisors, and wide incisive foramina (Maser and Storm, 1970). In contrast to A. pomo, A. longicaudus is generally larger overall, has nasals that extend further posteriorly relative to the maxillaries, lacks the abductor digiti secundi muscle and a full complement of lumbricales muscles, and differs in chromosome number and morphology (Johnson and George, 1991)."
Similar species
From Hayes (1996): "Arborimus longicaudus can be distinguished from all other sympatric arvicoline rodents by the combination of a reddish dorsum lacking a median stripe, a venter washed with reddish-orange hairs, and a well-haired tail that is not distinctly bicolored and is >50 mm long and >50% of length of head and body (Maser and Storm, 1970; Verts and Carraway, 1984)."
Key to the species of Arborimus
References
Hall ER. 1981. The mammals of North America. 2 vols. John Wiley and Sons, New York.
Hayes JP. 1996. Arborimus longicaudus. Mammalian Species (532):pp.1-5.
Howell AB. 1921. Description of a new species of Phenacomys from Oregon. Journal of Mammalogy, 2:98-100.
Jameson EW, Peeters HJ. 2004. Mammals of California (No. 66). Berkeley (CA, USA): University of California Press.
Maser C, Storm RM. 1970. A key to Microtinae of the Pacific Northwest (Oregon, Washington, Idaho). O.S.U. Book Stores, Inc., Corvallis, Oregon, 162 pp.
True FW. 1890. Description of a new species of mouse, Phenacomys longicaudus, from Oregon. Proceedings of the United States National Museum 13:303-304.
Verts BJ, Carraway LN. 1984. Keys to the mammals of Oregon. Oregon State University Book Stores, Inc., Corvallis, Oregon, 178 pp.