RODENTS OF LIBYA 103 



Gerbillus gerbillus aeruginosus, new subspecies 



Holotype. Adult male, skin and skull, USNM 325146, from El 

 Giof, Cufra Oasis, Cyrenaica Province, Libya; obtained Apr. 3, 1962, 

 by G. L. Ranck, original no. 1920. 



Specimens examined. Eighty-four, from Cyrenaica: Bzema Oasis, 

 8 (1 skin only); El Hauuari, Cufra Oasis, 36 (1 skin only); El Giof, 

 Cufra Oasis, 40 (2 skin only). 



Measurements. Averages and extremes of 16 adult males and 8 

 adult females from the type locality, with the measurements of the 

 type in brackets, are, respectively: Total length 205 (200-215), 

 205.4 (200-213), [206]; length of tail 117.7 (109-129), 120 (115-128), 

 [119]; length of hind foot 29.4 (28-32), 28.4 (27-31), [29]; length of 

 ear 13.2 (13-14), 12.8 (12-13), [13]; occipitonasal length of skull 28 

 (27.3-28.8), 27.4 (26.8-27.8), [28.4]; length of auditory bulla 10.3 

 (9.8-10.8), 10.3 (10.1-10.7), [10.4]; crown length of upper molariform 

 toothrow 3.5 (3.3-3.7), 3.5 (3.4-3.6), [3.5]; greatest breadth across 

 zygomatic arches 15 (14.6-15.5), 14.7 (14.3-15.1), [14.7]; least inter- 

 orbital breadth 5.7 (5.4-6.1), 5.7 (5.4-5.9), [5.9]; breadth of rostrum 

 at level of antorbital foramina 3 (2.7-3.3), 3 (2.9-3.1), [3]; greatest 

 length of nasals 10.3 (9.8-10.6), 10.1 (9.7-10.6), [10.4]. 



Diagnosis. Interauricular, subauricular, interorbital, and rostral 

 areas same color as dorsum and ranging from Ochraceous-Buff, to 

 Clay Color, to tawny-rust; circumorbital, postauricular spots, 

 mystacial and pectoral areas, fore and hind limbs, and entire under- 

 pays white; vibrissae short and white; fore and hind feet sparsely 

 haired dorsally and ventrally, and each bearing five digits with 

 claws; pinna of ear almost naked and Pale Orange- Yellow with a row 

 of buffy hairs on anterior margin; tail long and distinctly bicolored, 

 ranging from Capucine Buff to Cinnamon dorsally and from Pinkish 

 Buff to Light Buff ventrally and with a distinct pencil, Light Buff 

 ventrally, and varying in dorsal color from Avellaneous in darker 

 colored individuals to Pale Pinkish Cinnamon in paler animals. Skull: 

 Small and gracile; anterior palatine foramina short and elliptical in 

 shape; posterior palatine canals short and bowed slightly laterally; 

 teeth small; zygomata fragile and convergent anteriorly; braincase 

 slightly inflated and skull rather flattened in profile; auditory bullae 

 moderately inflated ventrally and partially transparent; basioccipitals 

 narrow anteriorly; basisphenoid reduced to a narrow rib between 

 anteromedial edges of auditory bullae; pterygoid fossae large and 

 forming a depression dorsal to pterygoid hamulae; supraorbital bead 

 projecting over dorsal rim of orbit. 



Comparisons. Compared with topotypical Gerbillus gerbillus 

 gerbillus from Alexandria Road, 5 kilometers northwest of the Pyramids 



