Psammomys vexillaris Thomas 1925

157.

Lesser Sand Rat

Psammomys vexillaris

French: Psammomys de Thomas / German: Schlanke Sandratte / Spanish: Gerbillo de arena menor

Other common names: Pale Sand Rat, Thin Sand Rat

Taxonomy. Psammomys vexillaris Thomas, 1925,

Bu Ngem (= Bondjem), Lybia. The taxon P. wvexillaris was considered a synonym of P. obesus by many authors, among them G. B. Corbet in 1978 and I. Ya. Pavlinov and team in 1990, but H.W. Setzer in 1957 and G. L. Ranck in 1968 considered it distinct. Latter opinion was followed by E. L. Cockrum and colleagues in 1977 on basis of skull morphology and chromosome number. Because P. vexillars is easily confused with P. obesus their distinction is a problem, and some authors still doubt the validity of P. vexillaris despite the chromosomal genetic difference. A geometric morphometric study by H. Khemiri and colleagues in 2016 confirmed that the two species are distinguishable in Tunisia. Monotypic.

Distribution. Arid regions of NE Algeria, Tunisia,and NW Libya.

Descriptive notes. Head—body 115-130 mm, tail 80-120 mm, ear 10-12 mm, hindfoot 30-35 mm. No specific data are available for body weight. The Lesser Sand Rat looks

slightly smaller and paler than the Fat Sand Rat (PF. obesus) and has shorter ears. Dorsal pelage is pale tawny, ventral one cream or white. Tail, length of which is ¢.86% of head-body length, ends with a pencil. Soles of hindfeet are partly haired. Tympanic bullae are inflated and represent 39% of Maximum length of skull. Chromosomal complement has 2n = 46, FN = 78.

Habitat. Not very well known, but the Lesser Sand Rat seems to prefer more sandy habitats than the Fat Sand Rat. Found in alluvial soils on roadsides and hillocks.

Food and Feeding. Like the Fat Sand Rat, the Lesser Sand Rat eats only chenopod plant parts.

Breeding. Reproduction is poorly known, but may be similar to that of the Fat Sand Rat.

Activity patterns. The Lesser Sand Rat is nocturnal and terrestrial, digging burrows.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Data Deficient on The IUCN Red List. The Lesser Sand Rat is probably notvery abundant, but is confused with the Fat Sand Rat in some ecological studies.

Bibliography. Cockrum et al. (1977), Corbet (1978), Fichet-Calvet (2013c), Khemiri et al. (2016), Kowalski & Rzebik-Kowalska (1991), Pavlinov et al. (1990), Ranck (1968), Setzer (1957).