115.

Greater Egyptian Gerbil

Gerbillus pyramidum

French: Grande Gerbille / German: Grote Agypten-Rennmaus / Spanish: Gerbillo de Egipto grande

Other common names: Burton's Gerbil

Taxonomy. Gerbillus pyramidum E. Geoffroy Saint-Hilaire, 1803,

Giza Province, Egypt. D. M. Lay in 1983 described a high chromosomal polymorphism within G. pyramdum, the distribution and constitution of which were debated by many authors. Several subsequent morphometric and chromosomal studies showed that the taxon is more widely distributed in sahelian zones of West Africa than initially recognized. D. J. Osborn and I. Helmy hypothesized in 1980 that, on basis of morphologicalattributes, G. pyramidum included also G. floweri + G. perpallidus; in molecular analysis in 2016, however, A. Ndiaye and colleagues tested that theory and found that G. floweri (with G. perpallidus as a synonym) represented a separate clade from G. pyramidum . Three subspecies recognized.

Subspecies and Distribution.

G.p.pyramidumEGeoffroySaint-Hilaire,1803—NEgypt.

G. p. elbaensis Setzer, 1958 — SE Egypt and NE Sudan (SE Eastern Desert).

On following pages: 116. Rupicolous Gerbil ( Gerbillus rupicola); 117. Khartoum Gerbil ( Gerbillus stigmonyx); 118. Berbera Gerbil ( Gerbillus acticola); 119. Brockman's Gerbil ( Gerbillus brockmani); 120. Dunn's Gerbil (Gerbillus dunni): 121. Mackilligin's Gerbil ( Gerbillus mackilligini); 122. Least Gerbil ( Gerbillus pusillus); 123. Rosalinda Gerbil (Gerbillus rosalinda); 124. Somalian Gerbil (Gerbillus somalicus); 125. Harwood's Gerbil (Gerbillus harwoodi); 126. Cheesman’s Gerbil (Gerbillus cheesmani); 127. Wagner's Gerbil (Gerbillus dasyurus); 128. Black-tufted Gerbil ( Gerbillus famulus); 129. Mesopotamian Gerbil ( Gerbillus mesopotamiae); 130. Balochistan Gerbil ( Gerbillus nanus): 131. Large Aden Gerbil ( Gerbillus poecilops); 132. Swarthy Gerbil ( Gerbillus aquilus); 133. Indian Hairy-footed Gerbil (Gerbillus gleadowi); 134. Somali Pygmy Gerbil (Microdillus peel); 135. Pouched Gerbil (Desmodilliscus braueri): 136. Fat-tailed Jird ( Pachyuromys duprasi); 137. Bushy-tailed Jird ( Sekeetamys calurus).

G. p. gedeedus Osborn & Helmy, 1980 — known from a few oases in Egypt. Also present in W Mauritania, and from Mali E to Sudan, but subspecies involved not known.

Descriptive notes. Head-body 102-135 mm, tail 128-180 mm, ear 14-20 mm, hindfoot 30-39 mm; weight 37-67 g. Males are slightly heavier and larger than females. The Greater Egyptian Gerbilis a large gerbil with orange-brown dorsal pelage sharply delineated on flanks from pure white venter. White spots are present on head around eyes, and hands and feet are white. Long feet bear hairy soles. Long tail (125-150% of head-body length) terminates in a more orless well-marked dark hair pencil. Female has four pairs of mammae. Chromosomal complement has 2n = 38, FNa = 72.

Habitat. Sandy habitats, oases with palm plantations, coastal plains and dunes. Greater Egyptian Gerbil may be found in grasslands with Panicum turgidum ( Poaceae) tussocks at base of Acacia (Fabaceae) and Tamarix (Tamaricaceae) trees. May be found also in anthropogenic habitats (e.g. edges of cultivated fields, irrigated canals, storehouses, gardens, and even houses).

Food and Feeding. The Greater Egyptian Gerbil is granivorous and herbivorous. It may store food (seeds) during wet season in orderto survive during dry season.

Breeding. In north Sudan, reproduction occurs during rainy season and dry cold season. Gestation lasts 22 days, and litter is of 2-5 young (mean 3). Juveniles are weaned at 25-30 days, and become mature in 3-4 months.

Activity patterns. The Greater Egyptian Gerbil is crepuscular and nocturnal, and terrestrial. It digs burrows with up to five entrances very similar to those of the Lesser Egyptian Gerbil ( G. gerbillus), where it spends day. It may also make use of burrows of other gerbil speciesat the base of bush or trees in sandy hills.

Movements, Home range and Social organization. The Greater Egyptian Gerbil appears to be abundant and seems to be gregarious.

Status and Conservation. Classified as Least Concern on The IUCN Red List owingto its abundance and wide distribution.

Bibliography. Abramsky et al. (1994), Dobigny, Nomao & Gautun (2002), Granjon & Duplantier (2009), Granjon, Bonnet et al. (1999), Granjon, Bruderer et al. (2002), Happold (1968), Lay (1983), Musser & Carleton (2005), Ndiaye, Chevret et al. (2016), Ndiaye, Tatard et al. (2016), Osborn & Helmy (1980).