Sorex tundrensis
Tundra Shrew
(Sorex tundrensis) | |
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Range | |
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Taxonomic classification | |
Order: | Eulipotyphla |
Suborder: | Erinaceota |
Family: | Soricidae |
Subfamily: | Soricinae |
Tribe: | Soricini |
Genus: | Sorex |
Subgenus: | Sorex (subgenus) |
Species group: | Sorex araneus group |
Binomial details | |
Sorex tundrensis Merriam, 1900 |
Description
Adult Tundra Shrews are striking and not easily confused with other shrews. The adults are noticeably tricolored in the summer and bicolored in the winter. Subadults also have a bicolored appearance, but it may be indistinct in some individuals. Adult shown in top two photos. Subadult shown in bottom three photos.
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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rangewide | Naughton (2012) | 83–120 | 22–37 | 11–15 | 4–10 | 4.9–14.0 |
Skull
Sorex tundrensis skull characters | |
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units in mm | |
Skull | |
Condylobasal length: | 17.0–18.5 (Junge & Hoffman, 1981) |
Postmandibular canal: | Present |
Shape: | Braincase is slightly rounded |
Dental | |
Upper unicuspids: | 5 |
Unicuspid notes: | U3>U4 |
Tines present: | Yes |
Tine size: | Medium |
Tine position: | Well below upper limit of pigment on upper incisors |
Shape upper incisors: | Parallel or slightly diverging |
Five unicuspids. Third unicuspid is larger than fourth. The inner side of the lower jaw contains a postmandibular canal. The tines on the upper incisors are small and positioned well within the upper line of pigment on the upper incisors.
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Lateral view of the skull of a subadult Sorex tundrensis. Long scale bar represents 1 cm; short scale bar represents 1 mm. -
Lateral view of skull of adult Sorex tundrensis. Long scale bar represents 1 cm; short scale bar represents 1 mm. Note that this is an older adult and the teeth are fairly worn. -
Unicuspids of Sorex tundrensis. Scale bar represents 1 mm. -
Upper incisors of Sorex tundrensis. Scale bar represents 1 mm.
Similar species
Adult Sorex tundrensis are quite distinct and not easily confused with any other species. However, subadults of Sorex tundrensis are sometimes confused with Sorex cinereus. Sorex tundrensis is quite a bit larger than S. cinereus and generally have a bicolored appearance. The tip of the tail in subadult S. tundrensis is somewhat tufted or bulbous in shape.
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References
Junge JA, Hoffman RS. 1981. An annotated key to the long-tailed shrews (Genus Sorex) of the United States and Canada with notes on middle American Sorex. Occasional Papers of the Museum of Natural History, The University of Kansas, Lawrence Kansas. Number 94; Pages 1-48. Link
Merriam CH. 1900. Papers from the Harriman Alaska Expedition. I. Descriptions of Twenty-six New Mammals from Alaska and British North America. Proceedings of the Washington Academy of Sciences 2, 16.
Naughton D. 2012. The natural history of Canadian mammals. Toronto (ON, CA): University of Toronto Press.