Sorex arizonae
| Arizona Shrew
(Sorex arizonae) | |
|---|---|
| Range | |
 | |
| Taxonomic classification | |
| Order: | Eulipotyphla |
| Suborder: | Erinaceota |
| Family: | Soricidae |
| Subfamily: | Soricinae |
| Tribe: | Soricini |
| Genus: | Sorex |
| Subgenus: | Incertae sedis |
| Species group: | Sorex merriami group |
| Binomial details | |
| Sorex arizonae Diersing & Hoffmeister, 1977 | |
| Other resources | |
| Full taxonomic details at MDD | |
Description
From Hoffmeister (1986): "A small, long-tailed shrew of the subgenus Sorex. Coloration of dorsum pale or grayish."
From Simons & Hoffmeister (2003): "Sorex arizonae is a small shrew with a gray to brown dorsum and slightly lighter venter (Diersing and Hoffmeister 1977; Hoffmeister and Goodpaster 1954)."
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 |
|---|---|---|---|---|---|---|
| Arizona (Pima and Cochise Cos.) | Hoffmeister (1986) | 93–114 (n=10) | 37–46 (n=10) | 11–13 (n=10) | ||
| Arizona (southern) | Simons and Hoffmeister (2003) | 92–109 (n=21) | 38–49 (n=21) | 11–13 (n=21) | 2.6–5.2 (n=19) | |
| not reported | Diersing and Hoffmeister (1977) | 93–114 (n=10) | 37–46 (n=10) | 11–13 (n=10) | ||
| rangewide | Wilson & Ruff (editors, 1999) | 79–114 | 37–55 | 1.9–5.2 |
Skull characters
| Sorex arizonae skull characters | |
|---|---|
| units in mm | |
| Skull | |
| Condylobasal length: | 15.7–16.53 (Diersing & Hoffmeister, 1977); 15.7–16.53 (Álvarez-Castañeda, 2024) |
| Postmandibular canal: | Present |
| Shape: | Braincase is slightly rounded (based on image from Diersing & Hoffmeister, 1977) |
| 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: | Straight |
| Dental characters: | Tips of upper incisors are more widely separated partly because of tines (Diersing & Hoffmeister, 1977) |
From Hoffmeister (1986): "A member of the subgenus Sorex, with postmandibular foramen present and upper unicuspids without pigmented ridge; third upper unicuspid larger than fourth; tines always present on medial sides of I1 (upper incisors); small in external and cranial size for most species of subgenus Sorex; zygomatic plate narrow; length of skull small, with occipitobasilar length under 16.5 mm; coloration of dorsum pale (grayish)."
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Dorsal view of the skull of Sorex arizonae. -
Ventral view of the skull of Sorex arizonae. Note that both tympanic bones are missing. -
Lateral view of the skull of Sorex arizonae. Long scale bar is 10 mm. -
Upper incisors of Sorex arizonae. Borrowed from Diersing & Hoffmeister (1977). -
Upper incisors of Sorex arizonae. -
Upper incisors of Sorex arizonae. -
Unicuspids of Sorex arizonae. Borrowed from Diersing & Hoffmeister (1977). The third upper unicuspid is equal to or larger than the fourth.
Similar species
From Simons & Hoffmeister (2003): "Sorex arizonae is distinguished from other shrews by the presence of a well-defined post-mandibular foramen, lack of pigmentation on lingual face of upper unicuspids, presence of medial accessory tines on I1 (upper incisor), third unicuspid larger than or subequal to fourth unicuspid, condylobasal length ~16.6 mm, and narrow palate (Diersing and Hoffmeister 1977; Junge and Hoffman 1981)."
Comparison with Sorex merriami
From Hoffmeister (1986): "S. arizonae differs from S. merriami by the presence of tines on the medial side of the first upper incisors, rather than none; breadth of palate, measured across P4, less than breadth measured across M3, where reverse is true in merriami; total and tail length slightly greater; unisucpid 3 equal to or slightly larger than unicuspid 4; upper molars with metacone-metastyle length noticeably greater than paracone-parastyle length; and not w-shaped as in merriami.
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Upper incisors of Sorex arizonae. Borrowed from Diersing & Hoffmeister (1977). 
Upper incisors of Merriam's Shrew (Sorex merriami). Borrowed from Diersing & Hoffmeister (1977).
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Unicuspids of Sorex arizonae. Borrowed from Diersing & Hoffmeister (1977). Unisucpid 3 is equal to or slightly larger than unicuspid 4. -
Unicuspids of Merriam's Shrew (Sorex merriami). Modified from Diersing & Hoffmeister (1977). Unisucpid 3 is larger than unicuspid 4.
Comparison with Sorex monticolus
From Hoffmeister (1986): "S. arizonae differs from S. monticolus in presence of a post-mandibular foramen; upper unicuspid 3 same size or larger than unicuspid 4 rather than smaller; upper unicuspids without pigmented ridge from apices to cingula, rather than such a pigmented ridge, unless teeth are greatly worn; secondary cusp on first upper incisor, viewed laterally, smaller and shorter; skull slightly shorter."
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Upper incisors of Sorex arizonae. Borrowed from Diersing & Hoffmeister (1977). -
Upper incisors of the Southern Montane Shrew (Sorex monticolus), Boulder County, Colorado, scale is 1 mm.
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Unicuspids of Sorex arizonae. Borrowed from Diersing & Hoffmeister (1977). Unisucpid 3 is equal to or slightly larger than unicuspid 4. -
Unicuspids of the Southern Montane Shrew (Sorex monticolus), scale is 1 mm. Unisucpid 3 is smaller than unicuspid 4.
References
Álvarez-Castañeda ST. 2024. Order Eulipotyphla. In Mammals of North America-Volume 1: Systematics and Taxonomy (pp. 397-513). Cham (Switzerland): Springer Nature Switzerland.
Diersing VE, Hoffmeister DF. 1977. Revision of the shrews Sorex merriami and a description of a new species of the subgenus Sorex. Journal of Mammalogy 58(3): 321-333.
Hoffmeister DF. 1986. Mammals of Arizona. Tucson (AZ, USA): University of Arizona Press.
Hoffmeister DF, Goodpaster WW. 1954. The mammals of the Huachuca Mountains, southeastern Arizona. Illinois Biological Monographs 24:1-152.
Simons LH, Hoffmeister DF. 2003. Sorex arizonae. Mammalian species (732):1-3.
Wilson DE, Ruff S, editors. 1999. The Smithsonian Book of North American Mammals. Washington D.C. (USA): Smithsonian Institution Scholarly Press.