RODENTS OF LIBYA 133 



of the Fezzan, and a large portion of southern Cyrenaica. As a result 

 of the present study, five subspecies of 67. c. campestris are now known 

 to occur in Libya. 



Ecological observations. Members of this species are the most 

 widely distributed of all Libyan rodents and occur in virtually all 

 habitats. In the larger oases where sandy areas and date palms are 

 widespread, gerbils belonging to the subgenus Gerbillus are more 

 abundant, and representatives of G. campestris are confined more to 

 the mesic habitats of the sedge pockets in the interior of the palm 

 groves or occur beyond the oasis proper in the zone of tamarix and 

 acacia. Apparently, G. campestris is not able to compete with these 

 sand-loving gerbils and is forced to inhabit these marginal habitats. 

 In a few cases, however, these gerbils occupied all habitats within the 

 oasis. Rocky areas appear to be preferred above all others; wherever 

 cliffs, rocky outcroppings, or talus are present, these rodents occur in 

 abundance. 



Gerbillus campestris brunnescens, new subspecies 



Holotype. Adult male, skin and skull, USNM 302180, from 5 km 

 SE Derna, Cyrenaica Province, Libya; obtained Nov. 9, 1955, by 

 H. W. Setzer, original no. 2724. 



Specimens examined. One hundred twenty-one, from Cyrenaica: 

 27 km E Apollonia, 3; 11 km SW Susa (= Apollonia), 5; 12 km SW 

 Apollonia, 2 (1 skin only); 12 km S Apollonia, 2; 5 km NW Labrag, 

 6 (1 skin only) ; 4 km W Labrag, 1 ; 12 km NW Gubba 3 (1 skin only) ; 

 3 km E Derna, 8; 5 km SE Derna, 27 (1 skin only) ; Wadi el Kuf, 13 

 km WSW Messa, 7; 10 km SW El Faidia, 6; 7 km NE Slonta, 1; 5 km 

 W Tocra, 29 (1 skin only); 20 km SW Tocra, 16; 10 km N Gerdes, 3; 

 2 km N Coefia, 2. 



Measurements. Averages and extremes of 15 males and 9 females 

 from the type locality, with the measurements of the type in brackets, 

 are, respectively: Total length 244.8 (228-262), 236 (223-252), 

 [248]; length of tail 143.1 (132-150), 137.8 (127-152), [148]; length of 

 hind foot 28.2 (27-30), 27.3 (27-28), [28]; length of ear 17.6 (17-19), 



17.2 (17-18), [18]; occipitonasal length of skull 30.3 (28.9-31.6), 29.5 

 (28.9-30.2) [30.2]; length of auditory bulla 9.3 (8.9-9.7), 9.3 (9-9.5), 

 [9.3]; crown length of upper molariform toothrow 3.9 (3.8-4.1), 4 (3.9- 

 4.2), [3.9]; greatest breadth across zygomatic arches 15.6 (14.7-16.6), 

 14.9 (14.4-15.2), [15.5]; least interorbital breadth 5.5 (5.2-5.9), 5.4 

 (5.2-5.7), [5.7]; breadth of rostrum at level of antorbital foramina 3.2 

 (3.1-3.4), 3.2 (3.1-3.3), [3.3]; greatest length of nasals 11.6 (11-12.8), 



11.3 (10.9-11.7), [11.2]. 



Diagnosis. Upperparts Sudan Brown becoming paler on sides and 

 scapular areas; all parts of dorsum with strong suffusion of blackish- 



