RODENTS OF LIBYA 121 



Gerbillus pyramidum tarabuli Thomas 



Gerbillus pyramidum tarabuli Thomas, Proc. Zool. Soc. London, vol. 2, pt. 1, p. 5, 

 October 1902 (Sebha, Fezzan Province, Libya). 



Specimens examined. Three hundred thirty-one, from Fezzan: 

 Brach, 22, Edri, 12; Temenhint, 34; 4 km N Sebha, 10; 5 km NW 

 Sebha, 8; 3 km NW Sebha, 10; Sebha, 19 (2 BM); 7 km SW Sebha, 

 5; 10 km SE Sebha, 1 ; El Abiad, 35 (3 skin only; 4 skeletons) ; Goddua, 

 15 (9 skull only); Meseguin, 33; Umm el Araneb, 14; Traghen, 12; 

 6 km N Murzuch, 26; 28 km E Murzuch, 3; Murzuch, 4; 12 km N 

 Ghat, 1; Ghat, 11; El Gatrun, 46; El Barcat, 10. 



Measurements. Averages and extremes of 17 adult males and 14 

 adult females from the vicinity of Sebha are, respectively: Total 

 length 271.4 (261-289), 256.9 (246-277); length of tail 153.8 (143- 

 165), 145.3 (132-155); length of hind foot 33.1 (31-35), 31.9 (30-35); 

 length of ear 16.2 (14-17), 15.3 (14-17); occipitonasal length of skull 

 34.1 (32.5-35.6), 32.9 (31.8-34.2); length of auditory bulla 11.9 

 (11.4-12.3), 11.6 (11.2-12.3); crown length of upper molariform 

 toothrow 4.3 (4-4.5), 4.2 (3.9-4.5); greatest breadth across zygomatic 

 arches 17.8 (17.2-18.6), 17.3 (16.7-17.8); least interorbital breadth 

 6.8 (6.5-7.4), 6.7 (6.3-7.1); breadth of rostrum at level of antorbital 

 foramina 3.5 (3.3-3.8), 3.5 (3.3-3.8); length of nasals 13.4 (12.7-14.3), 

 12.9 (12.4-13.5). 



Diagnosis. Upperparts ranging from Light Ochraceous-Buff to 

 Ochraceous-Buff, becoming paler on sides and flanks; entire dorsum 

 with grayish cast owing to alternate banding on individual hairs; 

 this grayish hue more concentrated in middorsal region ; postauricular 

 and supraorbital patches conspicuous and white; rostral, mystacial, 

 circumoral, and scapular areas, and entire underparts pure white; 

 this white extending dorsolaterally beyond the venter and forming 

 an abrupt line where it merges with the buffy color of the dorsum; 

 inner and outer surfaces of pinna of ear sparsely haired and Warm 

 Buff; eye ring black; vibrissae formed from about equal numbers of 

 light and dark hairs; dorsal and ventral surfaces of fore and hind feet 

 densely haired, each with five digits bearing claws; tail relatively long, 

 indistinctly bicolored, Light Ochraceous-Buff above and Pale Ochrace- 

 ous-Buff below, with prominent pencil (Wood Brown) extending along 

 distal one-third of tail; dorsum of tail with light admixture of brownish 

 hairs. Skull: Large and robust; zygomata heavy; anterior palatine 

 foramina small; post palatine canals narrow and slitlike; braincase 

 flattened; supraorbital bead prominent; auditory bullae narrow 

 transversely and ventrally inflated. 



Comparisons. In the shape and proportions of the skull, topotypes 

 of Gerbillus pyramidum tarabuli from the vicinity of Sebha, Fezzan 

 Province, Libya, are indistinguishable from specimens of Gerbillus 



285-134 O — 68 9 



