135.

Pouched Gerbil

Desmodilliscus braueri

French: Gerbille de Brauer / German: BrauerZwergrennmaus / Spanish: Gerbillo de abazones

Other common names: Brauer's Dwarf Gerbil

Taxonomy. Desmodilliscus braueri Wettstein, 1916,

south of El Obeid, Sudan.

Various revisions of D. braueri have revealed some geographical variability, but a morphometric study concluded that the taxon is better treated as monotypic. Three subspecies were recognized by H. W. Setzer in 1969, but that taxonomic treatment was refuted by D. R. Rosevear in the same year and by R. Hutterer and F. Dieterlen in 1986. On basis of morphoanatomical phylogeny, I. Ya. Pavlinov and colleagues included D. braueri in the Gerbillini tribe but in a distinct subtribe Desmodilliscina . In a 2005 study, P. Chevret and G. Dobigny found it to be a basal member of Gerbillinae. Monotypic.

Distribution. Sahelian savannas (18°-12° N) from Mauritania and Senegal E to N Sudan.

Descriptive notes. Head—body 50-73 mm, tail 32-46 mm, ear 6-10 mm, hindfoot 13-16 mm; weight 4-13 g. Small gerbil characterized by a wide and large head with a white eyebrow, white cheeks, and a short tail (55-65% of head-body length). Tail is hairy, but there is no pencil at tip. Dorsal pelage is yellowish gray, and venter white and well demarcated from the back. Hindfeet are small, with a naked sole. On the skull the opisthodont incisors bear a groove. On the lower mandible only two molars are present, instead of three as in other Gerbillinae. Tympanic bullae are very inflated, including the mastoid part (40% of the greatest length of skull), and the incisor foramina are wide and long. Females bear four pairs of mammae. Diploid numberis variable: 2n = 78 ( Senegal) or 76 (Niger), FNa = 104.

Habitat. The Pouched Gerbil prefers bush and scrubs in dry Acacia savannas on hard sandyto silty soils and gravels.

Food and Feeding. The Pouched Gerbil is probably granivorous;it eats millet in captivity.

Breeding. Reproduction is seasonal, and occurs at the end of the dry seasonin Senegal . Details have been observed only in captivity: after a gestation of 26 days, female produced 2-7 young each of 0-9 g; after 28 days young are weaned.

Activity patterns. The Pouched Gerbil is nocturnal and terrestrial, digging burrows.

Movements, Home range and Social organization. In Senegal the burrow is not very deep but with many entrances, and probably built for a group of individuals; A. R. Poulet estimated that 2—4 ind/ha are present and the species is probably social. Abundanceis relatively higher during droughts and lower after heavy rainfall.

Status and Conservation. Classified as Least Concern on The IUCN Red List in view of its wide distribution and absence of major threats. This gerbil is abundant to very abundant locally.

Bibliography. Chevret & Dobigny (2005), Dobigny, Nomao & Gautun (2002), Heim de Balsac (1967), Granjon (2013b), Granjon & Duplantier (2009), Granjon et al. (1992), Hutterer & Dieterlen (1986), Pavlinov etal. (1990), Poulet (1984), Rosevear (1969), Setzer (1969).