753.

Bolivian Big-eared Mouse

Auliscomys boliviensis

French: Phyllotis de Bolivie / German: Bolivien-GroRohrmaus / Spanish: Ratén de orejas grandes de Bolivia

Other common names: Bolivian Pericote

Taxonomy. Hesperomys boliviensis Waterhouse, 1846, “ Bolivia, near Potosi [Potosi].”

Auliscomys boliviensis is the type species of the genus Maresomys described by J. Braun in 199. Two subspecies recognized.

Subspecies and Distribution.

A.b.boliviensisWaterhouse,1846—AluplanoofNChileandWCBolivia.

A. b. flavidior Thomas, 1902 — Altiplano of SW Peru

Descriptive notes. Head-body 127 mm, tail 68-95 mm, ear 23-27 mm, hindfoot 26-30 mm; weight 55 g. See general characters of the genus under the Painted Big-eared Mouse (A. pictus) account. There is considerable variation in head-body length between Bolivian and Peruvian populations of the Bolivian Big-eared Mouse. Hair is long and soft. Dorsum is coarse mix of gray, brown, and buff or ocherous; sides are paler; muzzle is whitish; and ocherous lateral line is not always well-defined. Venter is whitish or pale gray, more or less washed with buff, and ocherous pectoral streak is often present. Ears are long and are covered internally with short yellow hair and externally with much longer, rusty yellow hair. Preauricular patch is prominent, ocherous and white; post-auricular patch is buffy cream to whitish. Hindfeet are comparatively larger than in congeners, with silvery white, gray, or buff dorsal surfaces, sometimes with ocherous metatarsal patch; soles are coarsely scutellated, naked, and blackish. Tail is shorter than head-body length (57-95%), bicolored, and often ocherous and whitish above becoming ocherous terminally below, without terminal pencil. Chromosomal complement is 2n = 22 and FN = 30 based on individuals from Peru and northern Chile and 2n = 20 based on individuals Oruro, Bolivia.

Habitat. Altiplano usually in open country with sparse vegetation, flatlands dominated by Parastrephia lepidophylla ( Asteraceae) shrubs, and grassy and rocky habitats at elevations of 3500-5000 m.

Food and Feeding. Bolivian Big-eared Mice mainly eat parts of plants, followed by lichens, mycorrhizal spores, and arthropods.

Breeding. Male Bolivian Big-eared Mice from different populations apparently enter reproductive activity at different times: at Pairumani (Peru), scrotal males were captured in July, and at Caccachara (Peru), after September. At Caccachara, pregnant females were captured on October, and at Caylloma (Peru), in December. Numbers of embryos were 3—4. Juvenile individuals were recorded in November. Sex ratio was 1:1. In Chile, a captive pair had three litters (in a year) of 3-5 young/litter.

Activity patterns. The Bolivian Big-eared Mouse is terrestrial and diurnal.

Movements, Home range and Social organization. In Chile, density of the Bolivian Big-eared Mouse was 153 ind/km?. It has been observed living among boulder-strewn slopes among yareta ( Azorella compacta, Apiaceae), stone walls, and even within abandoned tuco-tucos (Ctenomys) burrows and sharing burrows with Highland Yellowtoothed Cavy (Galea musteloides). In Oruro (Bolivia), seven and ten individuals were recorded occupying a small area (150 m?) in active tuco-tuco burrows.

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

Bibliography. Alvarez (2016), Anderson (1997), Braun (1993), Bernal, D'Elia et al. (2016), Cofré & Marquet (1999), Couve (1975), Eisenberg & Redford (1999), Hershkovitz (1962), Mann (1978), Pacheco (2002), Pearson (1951a, 1958), Pearson & Patton (1976), Peurach (1994), Pine et al. (1979), Ramirez et al. (2007), Salazar-Bravo (2015b), Silva (2005), Walker & Spotorno (1992), Zeballos et al. (2001).