Gerbillus cheesmani Thomas, 1919

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 : 35-38

Gerbillus cheesmani Thomas, 1919

Common name: Cheesman's gerbil.

Diagnosis: Typical small to medium-sized sand gerbil, Fur is very soft, color sandy buff dorsally, without black speckling on rump, ventral site white with a distinct line of demarcation. White patches above eye and behind ear present ( Figure 38). Soles of hindfoot hairy. Tail very long, more than head body length. Terminal pencil scanty. Hair bases above base of tail white. Skull with large tympanic bullae extending beyond the supraoccipital. Dentition similar to G. andersoni ( Figure 39 ).

Localities: Previous records. Al Ghamr, Al Jafr, El Quweira, Al Wisad, Al Qaţţāfī, Ad Dumaythat south of ar Ruwayshid ( Abu Baker & Amr, 2003a & b); Ad Dīsah, Ra’s an Naqb, Al Mudawwarah, Wādī Ramm (Abu Baker & Amr, 2004), ( Figure 40 ).

Habitat: The distribution of this gerbil is confined to soft wind-blown sand dunes areas. Cheesman’s gerbil was found to be the most solitary of the recorded rodents as no other species was collected in the same areas where it lives except for Al Ghamr where one G. nanus and one M. libycus were collected. Cheesman’s gerbil is a strictly nocturnal species, this activity pattern was also observed among captive animals. This gerbil occurs among Haloxylon persicum, Hammada salicornica and Anabasis articulata shrubs. Although specimens were trapped in higher numbers among H. salicornica and A. articulata communities, it was found to be the only rodent inhabiting Haloxylon persicum vegetation. It was caught in high numbers in flat sandy sheets south of Ruwaishid with Seidlittzia rosmarinus as the dominant vegetation, where as in Al Wisad, the red sand dunes are dominated with H. salicornica ( Abu Baker & Amr, 2003b) .

Burrow system of this species was described by Abu Baker & Amr (2003b). The number of openings ranges between three to five with only two main entrances showing signs of frequent use. Burrow entrances were found clumped near and around margins of shrubs where the soil is moderately hard. All burrow openings including the main entrance were always found plugged with fresh sand. Diameter of the openings ranged from 3 to 6 cm, while the tunnel width was about 4 cm. Tunnel length ranged from 20 to 118 cm and the maximum depth from the surface was about 82 cm. One to three food chambers containing H. salicornica seeds were found towards the end of tunnels as well as chambers containing faecal material. One to two nest chambers were found in the burrows, nests were located at tunnel ends at the depth of 25–45 cm. Dry vegetation was found as a nesting material.

Biology: Pregnant females were collected in March, August and September from Al Wisad. Within one burrow system, three and four suckling in two nesting chambers were observed during August. Juveniles were caught in August from Al Wisad and Al Dumaythat. The horned sand viper, Cerastes gasperettii and the desert monitor, Varanus griseus are likely the main predators of Cheesman’s gerbil ( Abu Baker & Amr, 2003b).

Remarks: G. cheesmani shows a 2N=38 and FN=72 (female specimen). The karyotype includes 16 metacentric, 16 submetacentric and 4 telocentric autosomes. The X is a medium-sized metacentric chromosome ( Abu Baker et al., 2009).

Figures

FIGURE 39.A. Dorsal,B. Ventral, C. Lateral views of the skull, and D. Upper maxillary teeth for Gerbillus cheesmani.

FIGURE 40. Distribution of Cheesman's gerbil, Gerbillus cheesmani.