88.

Anderson’s Gerbil

Gerbillus andersoni

French: Gerbille dAnderson / German: Anderson-Rennmaus / Spanish: Gerbillo de Anderson

Other common names: Allenby’s Gerbil

Taxonomy. Gerbillus andersoni de Winton, 1902,

Mandara, E Alexandria, Egypt.

Gerbillus andersoniincludes many synonyms and could represent a species complex. G. L.. Ranck noted two subspecies for Libya in 1968, and three were described for Egypt by D. J. Osborn andI. Helmy in 1980. In Israel, the subspecies allenbyi occurs. D. M. Lay in 1983, as well as G. G. Musser and M. D. Carleton in 2005, discussed the validity of G. anderson: and its limits. A molecular

analysis ofthe Egyptian representatives ofthe species by A. Ndiaye and coworkers in 2016 confirmed its validity, and indicated thatits sister taxon would be G. gerbillus . Two subspecies recognized.

Subspecies and Distribution.

G.a.andersonideWinton,1902—coastalNAfrica,fromTunisiaEtoEgypt. G. a. allenbyi Thomas, 1918 — Sinai (Egypt), Israel, Palestine, and W Jordan.

Descriptive notes. Head-body 70-115 mm, tail 90-135 mm, ear 14-18 mm, hindfoot 25-32 mm; weight 16-38 g. Sexual dimorphism present: males are larger and have longertail than females. In its original description, Anderson’s Gerbil was presented as a miniature of the Greater Egyptian Gerbil ( G. pyramidum). Anderson’s Gerbil is rather small, with hairy feet. Dorsal pelage is sandy orange to orange brown and the belly pure white. Tail is long (115-140% of head-body length) and with a light pencil of brown hairsattip. Inflated tympanic bullae (¢.30% of maximum length ofskull).

Standard karyotype is 2n = 40, FN = 80 for the Egyptian population. Habitat. Sandy areas (coastal sand dunes with Atriplex [ Amaranthaceae] shrubs) in North Africa, as well as “wadis” (ephemeral riverbeds), mountain slopes, palm groves. In the Negev desert ofIsrael, Anderson’s Gerbil was found in stabilized or semi-stabilized sand dunes. Food and Feeding. Anderson’s Gerbil is omnivorous and feeds on green parts of plants

(c.42%), seeds (c.35%), and insects (c.20%); there is some variation with season. Breeding. In Egypt, reproduction is strongly seasonal, most breeding taking place at the end of winter (January-March) and in spring (until June). Litters consist of 3-7 offspring, with mean ofthree. Young reach sexual maturity at ¢.5-5 months and

20-30 g in weight. Activity patterns. Anderson’s Gerbil is nocturnal and terrestrial. It digs burrows, where

it rests during the day. It forages at night for seeds. Movements, Home range and Social organization. In Israel, subspecies allenbyi is in competition with the sympatric Greater Egyptian Gerbil. Anderson’s Gerbil is solitary and aggressive. Intraspecific aggressive behaviors (biting, chasing, butting, fighting)

were reported to occur between both sexes for access to food sources. Status and Conservation. Classified as Least Concern on The IUCN Red List. Anderson’s Gerbil is a common species and can be found in various types of environment. Overgrazing and development ofirrigated cultures, as well as tourism development, may become threats. Recent conservation genetic analysis performed on Negev populations ofIsrael showed low nucleotide diversity for two mitochondrial genes (control region and cytochrome-c oxidase subunitII) in different populations, indicating recent population extension ofthis gerbil and presence of isolated populations,this due probably to its marked habitat specificity.

Bibliography. Abramsky (1984), Abramsky, Brand & Rosenzweig (1985), Abramsky, Rosenzweig & Brand (1985), Abramsky, Rosenzweig, Pinshow et al. (1990), Aulagnier etal. (2009), Bar et al. (1984), Brand & Abramsky (1987), Cockrum et al. (1976), Happold (2013a), Harrison & Bates (1991), Lay (1983), Musser & Carleton (2005), Ndiaye, Chevret et al. (2016), Ndiaye, Tatard et al. (2016), Osborn & Helmy (1980), Ovadia (1999), Ovadia et al. (2005), Qumsiyeh (1996), Ranck (1968), Rotkopf et al. (2010), Soliman & Wassif (1982), Wassif & Soliman (1980).