Zapus oregonus
| Oregon Jumping Mouse
(Zapus oregonus) | |
|---|---|
| Range | |
 | |
| Taxonomic classification | |
| Order: | Rodentia |
| Suborder: | Supramyomorpha |
| Infraorder: | Myomorphi |
| Superfamily: | Dipodoidea |
| Family: | Zapodidae |
| Genus: | Zapus |
| Binomial details | |
| Zapus oregonus Preble, 1899 | |
| 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) 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. The delineation of this taxon by Malaney et al. (2017) includes the following subspecies: Zapus princeps cinereus, Zapus princeps curtatus, Zapus princeps oregonus, and part of Zapus princeps utahensis. 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 currently does not exist. The following descriptions from Krutzsch (1954) are provided for subspecies that Malaney et al. (2017) subsumed under Zapus oregonus.
From Krutzsch (1954), describing then Zapus princeps cinereus from Raft River Mt’s in northwestern Utah and in isolated mountains in southern Idaho, which is now included in Zapus oregonus: "Size, medium; back with broad mid-dorsal band, varying from pale brown mixed with Pinkish-Buff to dark brown mixed with Warm-Buff or Ochraceous-Buff; sides varying from near Pinkish-Buff to near Ochraceous-Buff; ventral surface white to base of hairs, not suffused with other color; tail bicolored, pale brown above and white to yellowish-white below; ears dark, edged with white or yellowish-white; upper teeth divergent anteriorly; auditory bullae small; skull relatively long; zygomata relatively weak and not widely bowed; nasals wide posteriorly; pterygoid fossae relatively narrow."
From Krutzsch (1954), describing then Zapus princeps curtatus from Pine Forest Mt’s, Humboldt County, Nevada, which is now included in Zapus oregonus: "Size medium; back pale near Light Ochraceous-Buff with admixture of black hair forming dark dorsal band; sides lighter than back; lateral line faintly indicated; ventral surface white; tail bicolored, grayish-white to yellowish-white below and pale brown above; ears dark, edged with yellowish-white; feet grayish-white above; palatal bridge short; tooth-rows almost parallel; mastoid region of skull relatively narrow; incisive foramina wide posteriorly; narrow across zygomata; nasals relatively narrow posteriorly."
From Krutzsch (1954), describing then Zapus princeps oregonus from Southeastern Washington, eastern Oregon east of Cascades, northeastern California, central and northeastern Nevada, and southwestern Idaho, which is now included in Zapus oregonus: "Size large; back from near Light Ochraceous-Buff to near Cinnamon-Buff, usually overlaid with black hairs forming broad dorsal band, which in some individuals is almost black; sides lighter than back, from near Light Pinkish-Cinnamon to near Cinnamon-Buff and Ochraceous-Buff, often with black hairs interspersed; lateral line faintly marked or wanting; belly pure white; tail bicolored, grayish-brown above and grayish-white to yellowish-white below; ears dark, edged with color of sides; palatal bridge long; interorbital region broad; inferior ramus of zygomatic process of maxillary usually with median projection; auditory bullae relatively small; incisive foramina greatly enlarged posteriorly; tooth-rows divergent anteriorly; nasals narrow posteriorly."
From Krutzsch (1954), describing then Zapus princeps utahensis from Southeastern Idaho and extreme western Wyoming (Teton, Snake, and Uinta Mt’s) southward through Uinta, Wasatch, Oquirrh, and Beaver Mt’s of Utah, which is now partly included in Zapus oregonus: "Size, large; back from Cinnamon-Buff to Warm Buff overlaid with black hairs; sides lighter with less admixture of black hairs; lateral line indistinct, sometimes wanting; tail bicolored, brownish-black above, white to yellowish-white beneath; feet grayish-white above; ventral surface white to base of hairs; ears dark, edged with white to yellowish-white; skull large; palatal bridge relatively short; upper tooth-rows diverging anteriorly; occipitonasal length great; interorbital region broad; zygomata widely bowed; postpalatal notch anterior to posterior face of last molars; mastoid width 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 |
|---|---|---|---|---|---|---|
| Nevada (Humboldt County pine forests) | Hall (1946) | 213–235 (n=5) | 125–141 (n=5) | 30–33 (n=5) | ||
| Nevada (Ruby Mountains) | Hall (1946) | 236–250 (n=12) | 139–150 (n=12) | 32–35 (n=12) | ||
| Nevada (Toyabe Mountains) | Hall (1946) | 220–240 (n=14) | 125–147 (n=14) | 29–35 (n=14) | 21.5–28.5 (n=14) | |
| Oregon (Blue Mountain, Z. princeps oregonus type) | Preble (1899) | 250 | 154 | 33 | ||
| Oregon (east of Cascade Range) | Verts & Carraway (1998) | females: 209–254 (n=30); males: 220–256 (n=30) | females: 127–155 (n=30); males: 131–155 (n=30) | females: 30–35 (n=30); males: 30–38 (n=30) | females: 20.0–44.2 (n=30); males: 23.0–35.3 (n=30) |
Skull
According to Jones (1981): "paracone in the M1 and M2 is attached to the body of the tooth." 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 oregonus meets that of the Northwestern Jumping Mouse (Zapus saltator) and the Southern Pacific Jumping Mouse (Zapus pacificus), differentiating Z. oregonus 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 these species. Zapus oregonus can be differentiated from the Central Pacific Jumping Mouse (Zapus montanus) and the Northern Pacific Jumping Mouse (Zapus trinotatus) by the paracone in the M1 and M2 (upper molars) being attached to the body of the tooth; whereas in the latter two 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 oregonus proposed by Malaney et al. (2017). -
Range of Zapus saltator proposed by Malaney et al. (2017). -
Range of Zapus pacificus proposed by Malaney et al. (2017). -
Range of Zapus montanus proposed by Malaney et al. (2017). -
Dark area represents the range of Zapus trinotatus proposed by Malaney et al. (2017).
Taxonomic notes
Recently, molecular studies have found that the taxonomy and species delineations within Zapus are complex (Malaney et al., 2013). 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. The delineation of this taxon by Malaney et al. (2017) includes the following: Zapus princeps cinereus, Zapus princeps curtatus, Zapus princeps oregonus, and part of Zapus princeps utahensis. 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.
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Zapus princeps subspecies boundaries as defined by Krutzsch (1954). -
Distribution of Zapus oregonus based on genetic analyses and niche-based geographic distribution modeling by Malaney et al. (2017).
References
Hall ER. 1946. Mammals of Nevada. Berkeley and Los Angeles (CA, USA): University of California Press.
Krutzsch PH. 1954. North American jumping mice (genus Zapus). University of Kansas Publications, Museum of Natural History 7:349-472. Link.
Malaney JL, Demboski JR, Cook JA. 2017. Integrative species delimitation of the widespread North American jumping mice (Zapodinae). Molecular Phylogenetics and Evolution 114: 137-152.
Preble EA. 1899-08-08. Revision of the jumping mice of the genus Zapus. North American Fauna 15:1-44.
Verts BJ, Carraway LN. 1998. Land mammals of Oregon. Berkeley (CA, USA): University of California Press.