Zapus montanus
| Central Pacific Jumping Mouse
(Zapus montanus) | |
|---|---|
| Range | |
 | |
| Taxonomic classification | |
| Order: | Rodentia |
| Suborder: | Supramyomorpha |
| Infraorder: | Myomorphi |
| Superfamily: | Dipodoidea |
| Family: | Zapodidae |
| Genus: | Zapus |
| Binomial details | |
| Zapus montanus Merriam, 1897 | |
| Other resources | |
| Full taxonomic details at MDD | |
Recently, molecular studies have found that the taxonomy and species delineations within Zapus are complex (Malaney et al., 2013; Malaney et al., 2017). Malaney et al. (2017) recognized 9 species within Zapus, elevating some of the subspecies in Krutzsch's (1954) revision of jumping mice to species status. Genetic approaches by Malaney et al. (2017) supported elevating this taxon to species status, which they called Zapus orarius. However, the Mammal Diversity Database (2024) states: "the name montanus appears to have nomenclatural priority, being the oldest name for this species and replaces orarius". The delineation of this taxon by Malaney et al. (2017) includes the following subspecies: Zapus trinotatus eureka, Zapus trinotatus montanus, Zapus trinotatus orarius, and part of Zapus trinotatus trinotatus. The work of Malaney et al. (2017) has importantly exposed cryptic diversity and putative new species within Zapus. Further studies will be needed to fully understand new species boundaries and morphological variation.
Description
A formal species description for this taxon as delineated by Malaney et al. (2017) does not currently exist. The following descriptions from Krutzsch (1954) are provided for subspecies that Malaney et al. (2017) subsumed under this taxon. The description from Merriam (1897) is for the type specimen of Z. t. montanus.
From Krutzsch (1954), describing then Zapus trinotatus eureka from Northwestern coastal region of California, from Russian Gulch State Park, Mendocino County north to Trinidad, Humboldt County, which is now included in Zapus montanus: "Size medium; color dull; back near Ochraceous-Buff with heavy admixture of black hairs, forming broad dorsal band; sides from near Ochraceous-Buff to near Ochraceous-Salmon, sometimes with heavy admixture of black hairs; lateral line usually distinct, sometimes blending with color of belly and side; ventral surface usually suffused with color of sides; tail bicolored, dark brown above, white to yellowish-white below; feet grayish-white above; ears dark, edged with color of sides; auditory bullae large; pterygoid fossae broad; incisive foramina relatively short; palatal bridge short; maxillary tooth-rows relatively short; narrow across zygomata; braincase narrow; interorbital region narrow; zygomatic arch relatively short."
From Merriam (1897) for type specimen of Z. trinotatus montanus from Crater Lake, Oregon: "Size rather large; similar to Z. trinotatus, but somewhat smaller and duller (side less 'orange'), with shorter ears and feet, and differing slightly in cranial characters. Dorsal area sharply defined, grizzled dusky and yellowish; sides ochraceous, conspicuously lined with black hairs; inner side of legs to heel dusky; tail sharply bicolor: gray above, white beneath; fore and hind feet soiled white. Belly in young adults washed withe yellow."
From Krutzsch (1954), describing then Zapus trinotatus montanus from Crater Lake, Klamath County, Oregon, northward along the Cascade Range into Hood River County, Oregon, which is now included in Zapus montanus: Size medium; back near Ochraceous-Buff with admixture of black hair, resulting in a grizzled, broad, dorsal band; sides lighter than back, from near Ochraceous-Buff to near Pinkish-Cinnamon, and lined with black hair; lateral line distinct; underparts usually pure white, sometimes with slight suffusion of ochraceous on lower throat and upper chest; tail bicolored, brown above and yellowish-white below; ears dark, sometimes flecked with ochraceous, edged with yellowish-white; feet grayish-white above; braincase relatively narrow; zygomata relatively short; condylobasal length short; mastoid region relatively narrow; palatal bridge short; auditory bullae large; frontal region inflated; pterygoid fossae relatively narrow.
From Krutzsch (1954), describing then Zapus trinotatus orarius from Southern and western Marin County, California, which is now included in Zapus montanus: Size small; back dark ochraceous, usually overlaid with black hairs forming broad dorsal band; side lighter than back with admixture of black hairs; lateral line distinct, usually bright, near Ochraceous-Buff; under parts strongly suffused with ochraceous; tail bicolored, white to yellowish-white below and dark brown above; feet grayish-white above; ears dark, edged with yellowish-white or tan; skull small; zygomata narrow; braincase narrow; maxillary tooth-rows short; interorbital region narrow; incisive foramina short; palatal bridge relatively long; mastoid region relatively broad; occipitonasal length short.
From Krutzsch (1954), describing then Zapus trinotatus trinotatus from Pacific coastal region from Requa, Del Norte County, California, north in Oregon west of the Cascades, and in Washington including the Cascades; to southwestern British Columbia, which is a subspecies of trinotatus that is now partly included in Zapus montanus: Size large; back from near Ochraceous-Buff to near Tawny with admixture of black hair forming broad dorsal band; sides lighter than back from near Ochraceous-Buff to near Tawny; lateral line usually distinct; belly white, sometimes with faint suffusion of ochraceous on lower throat and upper chest; tail bicolored, brown above, white to yellowish-white below; ears dark, sometimes flecked with color of sides, edged with ochraceous; feet grayish-white above; palatal bridge relatively short; incisive foramina relatively long; condylobasal region long; zygomatic width great; braincase relatively broad; distance from incisors to postpalatal notch relatively great.
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 |
|---|---|---|---|---|---|---|
| California (Point Reyes, Z. orarius type) | Preble (1899) | 220 | 127 | 30 (dry) | ||
| Oregon (Cascade Range) | Verts & Carraway (1998) | females: 206–261 (n=12); males: 205–244 (n=30) | females: 115–144 (n=12); males: 123–149 (n=30) | females: 27–33 (n=12); males: 29–39 (n=30) | females: 17.5–32.0 (n=12); males: 18.3–37.9 (n=30) | |
| Oregon (Coast Range) | Verts & Carraway (1998) | females: 193–262 (n=30); males: 210–250 (n=30) | females: 116–159 (n=30); males: 118–160 (n=30) | females: 29–34 (n=30); males: 28–34 (n=30) | females: 18.7–34 (n=30); males: 19.0–35.4 (n=30) | |
| Oregon (Crater Lake, Z. montanus type locality) | Preble (1899) | 228 (n=8) | 135 (n=8) | 31 (n=8) | ||
| Oregon (Crater Lake, Z. t. montanus type locality) | Merriam (1897) | 230 (n=8) | 135.5 (n=8) | 31 (n=8) | ||
| Oregon (Crater Lake, Z. t. montanus type) | Merriam (1897) | 231 | 137 | 31 |
Skull
From Merriam (1897) for type specimen of Z. t. montanus from Crater Lake, Oregon: "Skull similar to that of Z. trinotatus, but somewhat smaller; palate narrower; incisive foramina narrower posteriorly; angular process of mandible less strongly developed. Contrasted with Zapus montanus the skull of Z. pacificus is smaller; the rostrum and nasals shorter; audital bullae smaller; basioccipital broader between bullae; interpterygoid fossa shorter; upper molar series more divaricating anteriorly."
From Jones (1981): "paracone in the M1 and M2 is isolated". See the Taxonomic notes section under Zapus for how the M1 and M2 characters noted by Jones (1981) were evaluated and applied to Malaney et al.'s (2017) species delimitations.
Similar species
Where the range of Zapus montanus meets that of the Northern Pacific Jumping Mouse (Zapus trinotatus) and the Southern Pacific Jumping Mouse (Zapus pacificus), differentiating Z. montanus from these two species may not currently be possible using morphological characters. A formal taxonomic revision of these three species is needed and may identify suitable characters for differentiating them. The Oregon Jumping Mouse (Zapus oregonus) can be differentiated from Z. montanus by the paracone in the M1 and M2 (upper molars) being attached to the body of the tooth; whereas in the latter species the paracone in the M1 and M2 is isolated (Jones, 1981). See the Taxonomic notes section under Zapus for how the M1 and M2 characters noted by Jones (1981) were evaluated and applied to Malaney et al.'s (2017) species delimitations.
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Range of Zapus montanus proposed by Malaney et al. (2017). -
Dark area represents the range of Zapus trinotatus proposed by Malaney et al. (2017). The light shaded area represents the former range of Z. trinotatus based on Krutzsch (1954). The former range to the south is now considered to be that of Z. montanus. -
Range of Zapus pacificus proposed by Malaney et al. (2017). -
Range of Zapus oregonus proposed by Malaney et al. (2017).
Taxonomic notes
From Krutzsch (1954): "The systematic status of Z. t. montanus has been in doubt. Several workers, for example, Howell (1920:227) and Preble (1899:28), considered it to be a species, and others (Merriam, 1897:104, Bailey, 1936:234) considered it to be a subspecies of Z. trinotatus." Krutzsch (1954) considered Z. montanus to be a subspecies of Z. trinotatus because of "the agreement of the two in size and shape of the baculum, diameter and pigment pattern of the hair, and the over-all proportions of the skull. In addition, animals from intermediate geographic areas are available and show actual intergradation." Genetic approaches by Malaney et al. (2017) supported elevating this taxon to species status, which they called Zapus orarius. However, MDD (2024) states: "the name montanus appears to have nomenclatural priority, being the oldest name for this species and replaces orarius". The delineation of this taxon by Malaney et al. (2017) includes the following: Zapus trinotatus eureka, Zapus trinotatus montanus, Zapus trinotatus orarius, and part of Zapus trinotatus trinotatus. Malaney et al. (2017) adds "additional tests are needed to asses if geographic variation in morphological characters best support the taxonomic models that they propose."
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Zapus trinotatus subspecies boundaries as defined by Krutzsch (1954). -
Distribution of Zapus montanus based on genetic analyses and niche-based geographic distribution modeling by Malaney et al. (2017).
References
Bailey V. 1936. The mammals and life zones of Oregon. North American Fauna 55:1-416.
Howell AB. 1920. A study of the California jumping mice of the genus Zapus. University of California Publications in Zoology 21:225-238.
Jones GS. 1981. The systematics and biology of the genus Zapus (Mammalia, Rodentia, Zapodidae)(Canada, United States) (Doctoral dissertation, Indiana State University).
Krutzsch PH. 1954. North American jumping mice (genus Zapus). University of Kansas Publications, Museum of Natural History 7:349-472. Link.
Malaney JL, Conroy CJ, Moffitt LA, Spoonhunter HD, Patton JL, Cook JA. 2013. Phylogeography of the western jumping mouse (Zapus princeps) detects deep and persistent allopatry with expansion. Journal of Mammalogy 94(5): 1016-1029. https://doi.org/10.1644/12-MAMM-A-006.1
Malaney JL, Demboski JR, Cook JA. 2017. Integrative species delimitation of the widespread North American jumping mice (Zapodinae). Molecular Phylogenetics and Evolution, 114, pp.137-152. https://doi.org/10.1016/j.ympev.2017.06.001
Mammal Diversity Database. 2024. Mammal Diversity Database (Version 1.13) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.10595931
Merriam CH. 1897. Three new jumping mice (Zapus) from the Northwest. Proceedings of the Biological Society of Washington 11:103-104.
Verts BJ, Carraway LN. 1998. Land mammals of Oregon. Berkeley (CA, USA): University of California Press.