Sorex
Appearance
Genus Sorex | |
---|---|
Taxonomic classification | |
Order: | Eulipotyphla |
Suborder: | Erinaceota |
Family: | Soricidae |
Subfamily: | Soricinae |
Tribe: | Soricini |
Sorex (long-tailed shrews) is a genus of small shrews found in North America and Eurasia. As the common name implies, members of this genus have long tails. As with all members of the tribe Soricini, Sorex have red-tipped teeth. Externally, they have somewhat long, pointed noses, tiny eyes and small ears that are often hidden by their fur.
Available taxon pages
The following subgenera are available on WhiskerWiki for this genus:
- Subgenus: Incertae sedis
- Clade I: Sorex clade B1
- Species group: Sorex trowbridgii group
- Species group: Sorex merriami group
- Clade I: Sorex clade B1
- Subgenus: Otisorex
- Clade I: Sorex clade A1
- Species group: Sorex vagrans group
- Species group: Sorex sonomae group
- Species group: Sorex palustris group
- Species group: Sorex monticolus group
- Species group: Sorex hoyi group
- Clade I: Sorex clade A2
- Clade I: Sorex clade A3
- Species group: Sorex oreopolus group
- Clade I: No information
- Species group: Sorex dispar group
- Clade I: Sorex clade A1
- Subgenus: Sorex
- Clade I: No information
Skull comparison
Accurate identification of shrews typically requires careful examination of the skull. Below is a table of skull characters that are most useful for identification.
Species | Number unicuspids | Postmandibular canal | Unicuspid notes | Tines upper incisors | Tine size | Tine position | Shape medial edge incisors | Skull shape | Dental characters | Condylobasal length |
---|---|---|---|---|---|---|---|---|---|---|
Sorex albibarbis | 5 | Absent | U3<U4 | Yes | Small | 19.1–21.7 (Beneski & Stinson, 1987); 18.4–19.2 (Álvarez-Castañeda, 2024) | ||||
Sorex arcticus | 5 | Present | U3≥U4 | Yes | Small | Well below upper limit of pigment on upper incisors | Straight | Skull relatively flat; braincase slightly rounded | Unicuspids robust and appear bulbous in ventral view; tips of upper incisors are more widely separated partly because of tines | 19.1–20.0 (Kirkland & Schmidt, 1996) |
Sorex arizonae | 5 | Present | U3≥U4 | Yes | Medium | Well below upper limit of pigment on upper incisors | Straight | Braincase is slightly rounded (based on image from Diersing & Hoffmeister, 1977) | Tips of upper incisors are more widely separated partly because of tines (Diersing & Hoffmeister, 1977) | 15.7–16.53 (Diersing & Hoffmeister, 1977); 15.7–16.53 (Álvarez-Castañeda, 2024) |
Sorex bendirii | 5 | Absent | U3<U4 | Yes | Medium | Slightly curved | Braincase only slightly rounded; rostrum shallow and distinctly downcurved | >19.3 (Pattie, 1973); 20.8–23.8 (Álvarez-Castañeda, 2024) | ||
Sorex cinereus | 5 | Absent | U3≥U4; U1–U4 are in an almost graduated series | Yes | Medium | Well below upper limit of pigment on upper incisors | Parallel or slightly diverging | Rounded braincase | Tips of upper incisors are more widely separated partly because of tines | 14.3–16.1 (French, 1980); 14.6–16.9 (Álvarez-Castañeda, 2024) |
Sorex dispar | 5 | Absent | U3≥U4 | Yes | Tiny | At or just below the upper limit of pigment on upper incisors | Diverging | Rostrum shallow; braincase bulbous; posterior border of the infraorbital foramen behind the space between the M1 and M2; mental foramen level with the space between p4 and m1 | 15.8–18.5 (Hall & Kelson, 1959); 16.45–18.7 (Kirkland, 1981); 15.35–18.7 (S. d. gaspensis; Kirkland, 1981); 18.4–19.2 (Álvarez-Castañeda, 2024) | |
Sorex eximius | 5 | Absent | U3 and U5 are tiny and vestigial | Yes | Large and long | Well below upper limit of pigment on upper incisors | Slightly curved | Skull relatively flat; braincase slightly rounded | U3 and U5 are barely or not at all visible in side view, but may be seen in occlusal view | 13.0–15.8 (Hall & Kelson, 1959); 15.0–16.2 (Álvarez-Castañeda, 2024) |
Sorex fontinalis | 5 | Absent | U3≥U4 | Yes | Small | Just below the upper limit of pigment on upper incisors | Diverging | Skull relatively flat | 14.63–15.85 (Kirkland & Levengood, 1987); 14.6–15.2 (Junge & Hoffman, 1981) | |
Sorex fumeus | 5 | Absent; occasionally present on one side | U3>U4 | Yes | Small | Just below the upper limit of pigment on upper incisors | Strongly curved and diverging | Braincase flattened, sometimes extremely; posterior border of the infraorbital foramen ahead of the space between the M1 and M2; mental foramen approximately level with the protoconid of m1 | Width of unicuspids exceeds length | 17.4–18.5 (Owen, 1984) |
Sorex haydeni | 5 | Absent | U3≥U4 | Yes | 14.2–15.1 (n=10; van Zyll de Jong, 1976); 15.0–16.1 (French, 1980); 14.1–15.9 (Álvarez-Castañeda, 2024) | |||||
Sorex hoyi | 5 | Absent | U3 and U5 are tiny and vestigial | Yes | Large and long | Well below upper limit of pigment on upper incisors | Slightly curved | Braincase is rounded | U3 and U5 are barely or not at all visible in side view, but may be seen in occlusal view | 13.0–15.8 (Hall & Kelson, 1959); 14.3–15.0 (Álvarez-Castañeda, 2024) |
Sorex jacksoni | 5 | Absent | U3≥U4 | Yes | 15.6–16.3 (Hall & Kelson, 1959) | |||||
Sorex longirostris | 5 | Absent | U3<U4; U3 and U4 sometimes subequal | Yes | Small | At or just below pigment line | Strongly diverging | Braincase is rounded | 13.8–15.6, except S. l. fisheri 15.4–16.4 (French, 1980) | |
Sorex lyelli | 5 | Absent | U3≥U4 | Yes | 15.2–15.4 (Hall & Kelson, 1959) | |||||
Sorex merriami | 5 | Present | U3>U4; U2 is largest | No | Converging | Braincase relatively flat | Tips of upper incisors are close together since teeth converge distally | 15.7–17.1 (Armstrong & Jones, 1971), 16–18 (Armstrong, 2010); 15.1–16.9 (Álvarez-Castañeda, 2024) | ||
Sorex minutissimus | 5 | Present | U3>U4 | 12.0–14.3 (Yudin, 1971) | ||||||
Sorex monticolus | 5 | Absent | U3<U4 | Yes | Small-medium | Below upper limit of pigment on upper incisors | Diverging | Braincase is rounded | 16.1–17.7 (Hennings & Hoffman, 1977); 16.1–19.2 (Junge & Hoffman, 1981) ; 16.2–16.7 (Álvarez-Castañeda, 2024) | |
Sorex nanus | 5 | Absent | U3<U4 | Yes | Medium | Below upper limit of pigment on upper incisors | Diverging | Braincase narrow and appears flattened when viewed from the side | A diagnostic dental measurement is the distance from the posterior border of the alveolus of the fifth unicuspid to the anterior margin of the alveolus of the incisor ranges between 1.8 and 2.4 mm. | 13.8–14.8 (Hoffman & Owen, 1980) |
Sorex navigator | 5 | Absent | U3<U4; U2>U1 | Yes; although lacking in some individuals | Tiny | Well below upper limit of pigment on upper incisors | Diverging | 19.1–21.7 (Beneski & Stinson, 1987); up to 22 (Armstrong, 2010) | ||
Sorex obscurus | 5 | Absent | U3<U4 | Yes | Small-medium | Below upper limit of pigment on upper incisors | Diverging | Skull somewhat slightly flattened | 16.1–17.7 (Hennings & Hoffman, 1977); 16.1–19.2 (Junge & Hoffman, 1981) | |
Sorex ornatus | 5 | Absent | U3<U4 | Yes | Medium | Below upper limit of pigment on upper incisors | Diverging | Relatively flat and broad and depressed interorbitally | Upper toothrow not crowded, with distinct triangular space between postero-medial edge of the fifth unicuspid and antero-medial edge of premolar; tips of upper incisors are more widely separated partly because of tines
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14.7–17.1 (Owen & Hoffman, 1983); 15.6–17.1 (Álvarez-Castañeda, 2024) |
Sorex pacificus | 5 | Absent | U3<U4 | No; but may have a median ridge | Slightly diverging (based on illustration in Carraway, 1985) | In ventral view, the unicuspids are wider than long | 19.0–22.8 (Junge & Hoffman, 1981); 21.4–23.0 (Álvarez-Castañeda, 2024) | |||
Sorex palustris | 5 | Absent | U3<U4 | Yes | Small | Below upper limit of pigment on upper incisors | Diverging | Rostrum straight or downcurved only slightly; braincase broad and flattened | 19.1–21.7 (Beneski & Stinson, 1987) | |
Sorex preblei | 5 | Absent | U3>U4; U1–U4 are in an almost graduated series | Yes | Long, acutely pointed | Below upper limit of pigment on upper incisors | Diverging | Skull relatively flat | 13.8–14.6 (Hoffman et al., 1969); less than or equal to 14.8 (Carraway, 1998); 13.8–15.1 (Álvarez-Castañeda, 2024) | |
Sorex pribilofensis | 5 | Absent | U3>U4 | 15.4–16.0 (Hall & Kelson, 1959) | ||||||
Sorex rohweri | 5 | Present | U3<U4 | Yes | Tiny | At or above the upper pigment edge | Diverging; slightly curved | Tines are are weak and often difficult to discern; pigmentation is pale or lacking (Woodman & Fisher, 2016) | 14.7–16.6 (Woodman & Fisher 2016) | |
Sorex sonomae | 5 | Absent | U3<U4; U5 usually rectangular | No | Parallel | Braincase is rounded | Unicuspids appear somewhat bulbous; fifth unicuspid is usually rectangular and is separated from the fourth premolar by a gap (Verts & Carrawy, 1998) | S. s. sonomae: 19.34–23.22 (Carraway, 1989); S. s. tenelliodus: 16.5–20.21 (Carraway, 1989) | ||
Sorex tenellus | 5 | Absent | U3<U4 | Yes | Tiny | Below upper limit of pigment on upper incisors | Diverging | Braincase is slightly rounded (based on images) | 14.5–15.3 (Hoffman & Owen, 1980) | |
Sorex trowbridgii | 5 | Present | U3<U4 | Yes | Small-medium | Below upper limit of pigment on upper incisors | Diverging and curved | Braincase is rounded | 16.8–18.8 (see George, 1989 for citations); 16.8–17.5 (Álvarez-Castañeda, 2024) | |
Sorex tundrensis | 5 | Present | U3>U4 | Yes | Medium | Well below upper limit of pigment on upper incisors | Parallel or slightly diverging | Braincase is slightly rounded | 17.0–18.5 (Junge & Hoffman, 1981) | |
Sorex ugyunak | 5 | Absent | U3≥U4 | Yes | Medium | Below upper limit of pigment on upper incisors | Slightly diverging | Braincase is rounded | Tips of upper incisors are more widely separated partly because of tines | 13.7–15.2 (Northwest Territories; van Zyll de Jong, 1976); 14.78 (n=26; van Zyll de Jong, 1976); 15.1–16.0 (northern Alaska; Bee & Hall, 1956; use with caution) |
Sorex vagrans | 5 | Absent; occasionally present on one side | U3<U4 | Yes | Small | At or above the upper edge of pigment; commonly there is a white or pale-colored area between the tine and body of the tooth | Diverging | Braincase is rounded | 15.5–17.5 (Gillihan & Foresman, 2004) |