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Perognathus alticola 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Rodentia Heteromyidae

Scientific Name: Perognathus alticola Rhoads, 1894
Common Name(s):
English White-eared Pocket Mouse
Synonym(s):
Perognathus alticolus Rhoads, 1894 [orth. error]
Taxonomic Source(s): Riddle, B.R., Jezkova, T., Eckstut, M.E., Oláh-Hemmings, V. and Carraway, L.N. 2014. Cryptic divergence and revised species taxonomy within the Great Basin pocket mouse, Perognathus parvus (Peale, 1848), species group. Journal of Mammalogy 95: 9-25.
Taxonomic Notes: Recent electrophoretic investigations confirm the specific separation of P. a. inexpectatus from P. parvus (though Patton in Wilson and Reede, 1993, 2005, stated that alticolus may be only subspecifically distinct from P. parvus). Best (1994), Baker et al. (2003), and Patton (in Wilson and Reeder 2005) listed alticolus as a distinct species.

Spelling corrected from alticolus to alticola: Despite contradictory published statements, the correct species name is alticola (not alticolus, the original spelling) in accordance with grammatical requirements of Latin, based on the opinion of the Nomenclature Committee of the American Society of Mammalogists (Erratum 2014). Based on detailed sequencing of nDNA and mtDNA genes, P. alticola is a member of the parvus species group of silky pocket mice, along with P. mollipilosus and P. parvus, and is sister-taxon to P. mollipilosus (Riddle et al. 2014). It may represent a smaller, disjunct, and isolated subspecies of P. mollipilosus: it lacks notable differentiation in nDNA and mtDNA genes that have been studied, and while it has a different FN compared to the neighboring P. mollipilosus xanthonotus (74 vs. 76, respectively), it has the same fundamental number as P. m. clarus (in Utah) within the variable FN of P. mollipilosus (70–76), and is only slightly different morphologically from that geographically adjacent species. Two subspecies are recognized:
  • P. a. alticola Rhoads, 1894 – SW USA (San Bernardino Mts, SW California), but may be extinct.
  • P. a. inexpectatus Huey, 1926 – SW USA (Tehachapi Mts, SW California).

Assessment Information [top]

Red List Category & Criteria: Vulnerable B1ab(i,iii,iv) ver 3.1
Year Published: 2017
Date Assessed: 2016-07-11
Assessor(s): Naylor, L. & Roach, N.
Reviewer(s): Amori, G.
Contributor(s): Hafner, D., Linzey, A. & Hammerson, G.A.
Justification:
White-eared Pocket Mouse is listed as Vulnerable because its extent of occurrence (EOO) is only 6,265 km², it is rare (with some subspecies not having been recorded for almost 90 years), no localities are within protected areas, and the extent and quality of its habitat is continuing to decline because of timbering and cattle grazing. Of the two recognized subspecies, one (P. a. alticola) has not been collected since 1934 and is now ossibly extinct.
Previously published Red List assessments:

Geographic Range [top]

Range Description:The White-eared Pocket Mouse is known from two disjunct mountain ranges in southern California in the United States: the San Bernardino Mountains in San Bernardino County (subspecies alticolus), and the Tehachapi Mountains, in Kern, Ventura, and Los Angeles counties (subspecies inexpectatus), at elevations of about 3,500-6,000 feet (1,070-1,830 m asl). The two subspecies are separated by the San Gabriel Mountains.
Countries occurrence:
Native:
United States (California)
Additional data:
Continuing decline in extent of occurrence (EOO):Yes
Number of Locations:2Continuing decline in number of locations:Yes
Lower elevation limit (metres):1070
Upper elevation limit (metres):1830
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Despite focused surveys, no specimens of subspecies alticolus have been obtained since the 1930s; this subspecies appears to be rare or extinct. Subspecies inexpectatus is also uncommon (D. F. Williams, cited by Best, 1994). Searches from 1979-1981, involving 81,938 trap nights, yielded only three specimens from a single locality (D. F. Williams). Trapping by Sulentich (1983) produced 11 specimens from two localities on the eastern side of Tehachapi Pass, in an area where a single specimen was caught in 1975 (Williams, 1978). Since 1978, occurrence at three localities has been verified; several historical sites for inexpectatus were not searched and probably still are occupied (D. F. Williams). The current population trend is unknown, but the species already appears to have declined to a small extent of occurrence, area of occupancy, number of subpopulations, and population size.
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Available information indicates that habitat is primarily open grassy/weedy/dry bracken areas among sagebrush and other shrubs in ponderosa/Jeffrey pine, pinyon/juniper, or montane hardwood-conifer associations. Secondary habitat is also open areas in Joshua tree and high desert shrub associations and old-field communities of herbaceous plants in high desert scrub associations, arid annual grassland (e.g., rangeland dominated by introduced grasses), and a fallow grain field dominated by Russian thistle (Sulentich, 1983; Williams, 1986; Best, 1994).

At higher elevations, this rodent is found in yellow pine forest with bracken fern and pinyon-juniper woodland habitats. At lower elevations, chaparral and coastal sage scrub habitat is occupied. It is a nocturnal species, remaining in burrows during the day and emerging at night to forage on a variety of plant and animal matter. Seeds are carried in cheek pouches to underground storage chambers.
Systems:Terrestrial
Continuing decline in area, extent and/or quality of habitat:Yes

Threats [top]

Major Threat(s): Current threats to the species are related to its increased vulnerability to habitat modification due to its restricted and patchy distribution (Nowak 1999). Habitat is used for timber production, but the effect of this is unknown. The species may be threatened by cattle grazing, but the effects of different levels of grazing are not known. Many of the mountain valleys within the potential range of subspecies alticolus are privately owned and have been developed or inundated by reservoirs; with exception of a Forest Service fire lookout tower, the area surrounding Strawberry Peak is privately owned and largely developed (Winter 1998).

Conservation Actions [top]

Conservation Actions: This species is not listed as threatened or endangered; some historical localities are on public land but habitat is unprotected. Further surveys are needed in potential habitat throughout its historical range and in contiguous potential habitat. Areas likely to support populations are the mountain slopes of the Tehachapi and San Gabriel ranges that front on the Mojave Desert (Williams, 1986). All known occurrences should be protected, but no data are available to determine the type of protection needed, other than protection from development. Information is needed on basic biology, ecology, and the taxonomic relationship between the two subspecies.

Citation: Naylor, L. & Roach, N. 2017. Perognathus alticola. The IUCN Red List of Threatened Species 2017: e.T16631A22224213. . Downloaded on 21 October 2017.
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