85.

Cape Short-tailed Gerbil

Desmodillus auricularis

French: Gerbille & queue courte / German: Kurzschwanzrennmaus / Spanish: Gerbillo de cola corta de El Cabo

Other common names: Namaqua Gerbil

Taxonomy. Gerbillus auricularis A. Smith, 1834,

“South Africa,—Mountains of Little Namaqualand, [Kamiesberg].”

Initially described as a Gerbillus, D. auricularis was later separated in genus Desmodillus on basis of its distinctive morphological characters, especially the tympanic bullae. Various authors have subsequently reviewed this taxon, which is presentlystill considered monospecific. Desmodillus has been placed in tribe Taterillini and (together with Gerbillurus) in subtribe Gerbillurina by several authors, including I. Ya. Pavlinov and colleagues in 1990, G. G. Musser and M. D. Carleton in 2005, and I.

Ya. Pavlinov in 2008. L. I. Knight and colleagues noted in 2013 that Desmodillus and Gerbilliscus comprise a monophyletic group of gerbils which last shared a common ancestor approximately eight million years ago. Phylogenetic analysis of morphological, chromosomal, and molecular data have not, however, confidently resolved the phylogenetic position of Desmodillus, but recent molecular studies show it to be a basal lineage in the Taterillini, a conclusion supported by its retention of a primitive dental character. Monotypic.

Distribution. SW Angola, Namibia, Botswana, and South Africa; possibly present in S Zimbabwe but not yet demonstrated.

Descriptive notes. Head-body 86-129 mm, tail 70-98 mm, ear 10-14 mm, hindfoot 21-29 mm; weight 29-82 g. The Cape Short-tailed Gerbil is a relatively small species of Gerbillinae with rather short (75-80% of head-body length) tail lacking terminal pencil. Dorsal pelage is ocherous orange to tawny brown and is soft and dense. Ventral pelage is pure white and there is a post-auricular white patch. Hindfeet bear hairy soles. Skull is robust, with very large tympanic bullae (larger than for any other species of Gerbillinae) reaching c.41% of maximum length of skull. Females bear four pairs of mammae. Karyotype 2n = 52.

Habitat. Open areas in South West Arid and Cape regions of South Africa. The Cape Short-tailed Gerbil prefers either hard or consolidated soils with low shrubs or sparse grasslands. It is never found in sand-dune habitats.

Food and Feeding. Cape Short-tailed Gerbils are omnivorous, and their diet includes seeds, insects, and green leaves. They forage on the ground andeat close to their burrows; they will store vegetable matter inside the burrow or in concealed places in the territory. They do not need waterto survive, and have developed physiological mechanisms to utilize body water at maximum efficiency.

Breeding. Reproduction can occur throughout the year, but seems to reach a peak during wet season. After 21 days of gestation, females may give birth to 2—4 offspring, which are blind and naked. Young open eyes at day 21 and are weaned at day 33.

Activity patterns. The Cape Short-tailed Gerbil is a nocturnal, terrestrial rodent. It can dig extensive burrows with many entrances, many cul-de-sacs, and food-storage chambers 30-60 cm deep.

Movements, Home range and Social organization. Cape Short-tailed Gerbils are solitary and asocial, though some burrows can be close and linked with pathways. Females are dominant over and aggressive toward males in captivity except during times of copulation.

Status and Conservation. Classified as Least Concern on The IUCN Red List. There are no major threats to the Cape Short-tailed Gerbil, which is found in many natural areas.

Bibliography. Chevret & Dobigny (2005), Colangelo et al. (2007), Dempster et al. (1993), Granjon et al. (2012), Griffin (1990), Happold (2013a), Knight et al. (2013), Musser & Carleton (2005), Nel & Rautenbach (1975), Pavlinov (2008), Pavlinov et al. (1990), Skinner & Smithers (1990), Qumsiyeh, Hamilton & Schlitter (1987), Qumsiyeh, Schlitter & Disi (1986).