Sorex tundrensis
| Tundra Shrew
(Sorex tundrensis) | |
|---|---|
| Range | |
 | |
| Taxonomic classification | |
| Order: | Eulipotyphla |
| Suborder: | Erinaceota |
| Superfamily: | Soricoidea |
| Family: | Soricidae |
| Subfamily: | Soricinae |
| Tribe: | Soricini |
| Genus: | Sorex |
| Subgenus: | Sorex (subgenus) |
| Species group: | Sorex araneus group |
| Binomial details | |
| Sorex tundrensis C. H. Merriam, 1900 | |
| Other resources | |
| Full taxonomic details at MDD | |
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.
Museum type specimens
-
Holotype: USNM 99286. Sorex tundrensis. Adult. Sex not given. Saint Michaels (Saint Michael), Alaska. Collected 13 September 1899. -
Holotype: USNM 99286. Sorex tundrensis. Adult. Sex not given. Saint Michaels (Saint Michael), Alaska. Collected 13 September 1899.
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 |
|---|---|---|---|---|---|---|
| rangewide | Naughton (2012) | 83–120 | 22–37 | 11–15 | 4–10 | 4.9–14.0 |
Skull
| Sorex tundrensis skull characters | |
|---|---|
| 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.
-
Holotype: USNM 99286. Sorex tundrensis. Adult. Sex not given. Saint Michaels (Saint Michael), Alaska. Collected 13 September 1899. Dorsal view of the skull. -
Holotype: USNM 99286. Sorex tundrensis. Adult. Sex not given. Saint Michaels (Saint Michael), Alaska. Collected 13 September 1899. Ventral view of the skull. -
Holotype: USNM 99286. Sorex tundrensis. Adult. Sex not given. Saint Michaels (Saint Michael), Alaska. Collected 13 September 1899. Lateral view of the skull. -
Holotype: USNM 99286. Sorex tundrensis. Adult. Sex not given. Saint Michaels (Saint Michael), Alaska. Collected 13 September 1899. Dorsal view of the mandible. -
Holotype: USNM 99286. Sorex tundrensis. Adult. Sex not given. Saint Michaels (Saint Michael), Alaska. Collected 13 September 1899. Lateral view of the mandible. -
NEON01IKV. Lateral view of the skull of a subadult Sorex tundrensis. Long scale bar represents 1 cm; short scale bar represents 1 mm. -
NEON01IJB. 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. -
NEON01IKV. Unicuspids of Sorex tundrensis. Scale bar represents 1 mm. -
NEON01IKV. Upper incisors of Sorex tundrensis.
Similar species
Comparison with Sorex cinereus
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.
-
Tundra Shrew (Sorex tundrensis) subadult -
Masked Shrew (Sorex cinereus) -
Tundra Shrew (Sorex tundrensis) upper incisors -
Masked Shrew (Sorex cinereus) upper incisors -
Tundra Shrew (Sorex tundrensis) unicuspids -
Masked Shrew (Sorex cinereus) unicuspids -
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.