309.

Southern Rock Deermouse

Peromyscus difficilis

French: Péromyscus des rochers / German: Sidliche Felsen-Hirschmaus / Spanish: Raton ciervo de roca meridional

Other common names: Zacatecan Deermouse

Taxonomy. Vesperimus difficilis J. A. Allen, 1891, Sierra de Valparaiso, Zacatecus, Mexico.

Peromyscus difficilis is in the true: species group. Its taxonomy was revised in 1961 and 1976. More recent biochemical, karyotypic, and DNA sequence data indicate that griseus, nasutus, and penicillatus forms should be assigned to P. nasutus . Five subspecies recognized.

Subspecies and Distribution.

P.d.difficilisJ.A.Allen,1891—fromSWChihuahuaSEtoGuanajuatoandN&WQuerétaro,Mexico.

P.d.amplusOsgood,1904—SHidalgo,extremeWVeracruz,NMéxico,Puebla,andNWOaxaca,Mexico.

P.d.felipensisMerriam,1898—C&SMéxico,DistritoFederal,extremeWPuebla,andCOaxaca,Mexico.

P.d.petricolaHoffmeister&delaTorre,1959—extremeSECoahuila,SNuevoLeon,NEZacatecas,NSanLuisPotosi,andextremeSWTamaulipas,Mexico.

P. d. saxicola Hoffmeister & de la Torre, 1959 — restricted to E Querétaro and N Hidalgo, Mexico.

Descriptive notes. Head-body 88-105 mm,tail 91-145 mm, ear 17-28 mm, hindfoot 22-28 mm; weight 24-32 g. The Southern Rock Deermouse is medium-sized, with grayish brown, yellowish brown, or brownish ocherous dorsum. Sides are yellowish, with distinct lateral line. Venteris whitish, suffused with gray or silver underfur; some subspecies have ocherous pectoral spot. Tail is bicolored and generally as long as or longer than head-body length. Ears are relatively large. Hindfeet are whitish. The Southern Rock Deermouse can be distinguished from the Perote Deermouse ( P. bullatus) and the Northern Rock Deermouse ( P. nasutus) byits larger body size and longer occipitalnasal length.

Habitat. Rocky areas in pine-oak forests and high-elevation desert scrublands and grasslands at elevations of 1200-3700 m.

Food and Feeding. The Southern Rock Deermouse mainly eats seeds but also plant stems and roots.

Breeding. Reproduction occurs in June-November. Litters have 2-3 young.

Activity patterns. The Southern Rock Deermouse is presumably nocturnal. It is usually associated with rock crevices and tree stumps, trunks, and cavities, where nests are constructed.

Movements, Home range and Social organization. Densities are 27-584 ind/ha.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Carleton (1989), Chavez & Ceballos (2014), Ceballos & Galindo (1984), Diersing (1976), Durish et al. (2004), Fernandez et al. (2010), Hall (1981), Hernandez-Chavez (1990), Hoffmeister & de la Torre (1961), Musser & Carleton (2005), Zimmerman, Hart & Kilpatrick (1975), Zimmerman, Kilpatrick & Hart (1978).