RODENTS OF LIBYA 87 



In color and overall body size, members of G. aureus from Libya 

 closely resemble representatives of Gerbillus pyramidum hirtipes 

 Lataste from Ain Sefra, southwestern Algeria, but differ from the 

 latter in having; noticeably longer tails. Cranially, the two groups 

 are of comparable size, but can be distinguished by the more massive, 

 compact skulls, heavier zygomata, and wider rostra of the Algerian 

 specimens. Ellerman and Morrison-Scott (1951), in keeping with their 

 objective of simplifying nomenclature, relegated Lataste's Gerbillus 

 hirtipes (1882) to subspecific status under the more widely distributed 

 Gerbillus pyramidum. At this time Tripolitania and the coastal areas 

 of western Libya were not represented by specimens, and Gerbillus 

 aureus was unknown. In the majority of external and cranial characters 

 these specimens from Algeria are much closer to G. aureus than to G. 

 pyramidum; in fact, they bear little resemblance to the latter. When 

 more localities in Algeria are represented by specimens of G. aureus and 

 G. pyramidum and when topotypes of G. p. hirtipes are available for 

 comparison, the latter will probably be reinstated as a full species, 

 distinct from either G. aureus or G. pyramidum but more closely re- 

 lated to the former, or aureus and hirtipes may be regarded as con- 

 specific, in which case the older hirtipes will take precedence. 



Ecological observations. Vegetated dunes are apparently the 

 preferred habitat of this gerbil, but they occur also in the littoral 

 deserts where dunes are usually lacking. In the Gebel Nefusa, the 

 habitat consists of rolling uplands with rather dense vegetative cover, 

 and sand, if present, is usually localized. 



Gerbillus aureus aureus Setzcr 



Gerbillus pyramidum. aureus Setzer, Proc. Biol. Soe. Wash., vol. 69, pp. 179-180, 

 Dec. 31, 1956 (12 km W Zliten, Tripolitania Province, Libya). 



Specimens examined. Forty, from Tripolitania: 12 km W 

 Zliten, 12; 25 km N Gharian, 8; 20 km E Rumia, 8 (1 skin only) ; 3 km 

 E Rumia, 10; 12 km S Chicla, 2. 



Measurements. Averages and extremes of six adult males and 

 measurements of two adult females, 302073 and 302075, from the 

 type locality, are: Total length 236.8 (223-244), 222, 230; length of 

 tail 131.8 (127-137), 125, 129; length of hind foot 30.7 (30-31), 30, 

 30; length of ear 15.2 (13-18), 13, 13; occipitonasal length of skull 

 30.7 (29.9-31.6), 29.2, 30; length of auditory bulla 11.1 (10.9-11.2), 

 10.7, 10.9; crown length of upper molariform toothrow 4.1 (4-4.3), 4.1, 

 4.1; greatest breadth across zygomatic arches 16 (15.6-16.5), 15.6, 

 15.9; least interorbital breadth 5.7 (5.5-6), 5.4, 5.4; breadth of ros- 

 trum at level of antorbital foramina 3 (2.9-3.1), 2.8, 2.9; greatest 

 length of nasals 11.7 (11.4-11.9), 11, 11.5. 



