Gerbillus andersoni de Winton, 1902

Amr, Zuhair S., Abu, Mohammad A., Qumsiyeh, Mazin & Eid, Ehab, 2018, Systematics, distribution and ecological analysis of rodents in Jordan, Zootaxa 4397 (1), pp. 1-94 : 34

Gerbillus andersoni de Winton, 1902

Common name: Anderson’s gerbil.

Diagnosis: This is a medium sized gerbil closely resembling other hairy-footed gerbils. Hair on the back is yellowish with gray buff, darker than G. gerbillus . Tail is densely covered with hair throughout, terminating in a small tuft, terminal pencil intermediate in size between the well-developed of G. gerbillus and the scanty tuft in G. cheesmani . Under parts are pure white with a distinct line of demarcation ( Figure 35 ). The dark pigmentation of its ears distinguishes this species from the other hairy-footed gerbil found in Jordan. Head and body length measures between 88–90 mm and tail length between 126–128 mm. It is slightly larger than G. gerbillus . White spots are found above eyes and behind ears. Skull of G. andersoni is slightly larger than that of G. gerbillus . Greatest length of the skull may reach up to 29.0 mm. Tympanic bulla not developed. Posterior margin of the nasal bone is truncate. Incisive foramina long, exceeding tooth row length, while posterior foramina relatively short. Posterior margin of mastoid chamber extends to level of occipital condyle but never exceeds supraoccipital bone. Posterior superior margin of mastoid chamber more inflated than inferior margin ( Figure 36 ).

Localities: Previous records. G. gerbillus = El Quweira ( Allen, 1915) ; 22 km N El Quweira, 5 Km S Ra’s an Naqb ( Atallah & Harrison, 1967); S Ra’s an Naqb (Abu Baker & Amr, 2004) ( Figure37 ).

Habitat: G. andersoni is found in areas of light sand dunes dominated with Anabasis articulata . It lives in association with the hairy-footed gerbil, G. cheesmani and the fat sand rat, Psammomys obesus . Burrows of G. andersoni could not be distinguished from those of G. cheesmani . Anderson's gerbil is a strictly nocturnal species ( Abu Baker & Amr, 2003a).

Biology: Anderson’s gerbil is a nocturnal animal, specialized on seeds (i.e. Thymelea hirsute ). It breeds in late winter or early spring, coinciding with the annual seed shedding. Female gives birth to a litter of three to seven offspring after a gestation period that lasts for 20 to 22 days.

Remarks: The distribution of this species is known only from the sand desert south of Ra’s an Naqb. Its presense in Jordan may represent a relict population. G. andersoni have 2N=40 and FN = 80 (male specimen). There are 14 metacentric and 24 submetacentric autosomes. The X and Y chromosomes are medium and smallsized submetacentric, respectively ( Abu Baker et al., 2009).

Figures

FIGURE 35. Anderson’s gerbil, Gerbillus andersoni (photo by Mohammad Abu Baker).

FIGURE 36. A. Dorsal,B. Ventral, C. Lateral views of the skull, and D. Upper maxillary teeth for Gerbillus andersoni.

FIGURE 37. Distribution of Anderson’s gerbil, Gerbillus andersoni.