72.

Dune Hairy-footed Gerbil

Gerbilliscus tytonis

French: Gerbille des dunes / German: Diinen-Haarsohlenrennmaus / Spanish: Gerbillo de pies peludos de duna

Other common names: Namib Dune Gerbil

Taxonomy. Gerbillus tytonis Bauer & Niethammer, 1960,

Sossusvlei, Namib Desert, Namibia.

Gerbilliscus tytonis was first described under Gerbillus and later associated with G. vallinus in Gerbillurus . It was accorded its present rank by D. A. Schlitter in 1973 on basis of its chromosomal characters. L. Granjon and colleagues in 2012 found that it belongs in a clade with G. paeba and G. setzeri . Monotypic.

Distribution. W Namibia, from Swakopmund to Luderitz.

Descriptive notes. Head-body 90-108 mm, tail 113-141 mm, ear 12-14 mm, hindfoot 28-36 mm; weight 25 g. This small gerbil has dark reddish-brown dorsal pelage and white belly, the head with white cheeks and supraorbital spots. Hindfeet soles are hairy and each digit bears fringes of hairs. Tail is rather long (128% of head-body length). Skull is remarkable in displaying a very short posterior palatal foramen. Tympanic bullae are inflated and extend posteriorly. Females bear three pairs of mammae. Chromosomal complement has 2n = 36, FN = 68.

Habitat. Sand dunes of Namib Desert up to 300 m high and having relatively high plant species richness. Never found in areas of compact or rockysoils.

Food and Feeding. Diet includes seeds, green parts of plants, arthropods, and insects, proportions varying between winter and summer. The Dune Hairy-footed Gerbilis considered a very opportunistic species because of wide variations in diet.

Breeding. Breeding peak during December—May. In captivity, litter size was 2-6 (average 4-4) young. Eyes open at 22-24 days.

Activity patterns. The Dune Hairy-footed Gerbil is nocturnal and terrestrial, digging deep burrows (larger than 2 m deep) with one or two entrances, and nest chamber lined with shredded vegetation and food caches. Burrow is situated close to Trianthema herreroensis ( Aizoaceae) and Stipagrostis sabulicola (Poaceae) in microhabitats formed by nara melon ( Acanthosicyos horridus, Cucurbitaceae).

Movements, Home range and Social organization. The Dune Hairy-footed Gerbil may sand-bathe at the entrance of a burrow. Population varies between summer and winter, and reaches a peak in autumn with 0-3-18-2 ind/ha. It is aggressive in captivity and fights for dominance (chasing, mutual boxing). Individuals communicate with footdrumming and ultrasonic whistles, and vocalizations are heard during contacts and copulation.

Status and Conservation. Classified as Least Concern on The IUCN Red List (as Gerbillurus tytonis). This species is present in many protected areas.

Bibliography. Granjon et al. (2012), Happold (2013a), Perrin, Dempster, Downs & Boyer (1999), Schlitter (1973).