106 U.S. NATIONAL MUSEUM BULLETIN 275 



Gerbillus gerbillus discolor, new subspecies 



Holotype. Adult male, skin and skull, USNM 322461, from Ghat, 

 Fezzan Province, Libya; obtained Dec. 18, 1961, by G. L. Ranck, 

 original no. 1116. 



Specimens examined. One hundred sixty-two, from Tripolitania: 



2 km SW Hun, 18; 5 km S Socna, 6; Bir Fergian, 10 km S Socna, 2; 

 from Fezzan: Edri, 11; Temenhint Oasis, 30 km NE Sebha, 12; 



3 km NW Sebha, 5; 5 km NW Sebha, 3 (1 skin only); 10 km SE 

 Sebha, 4 (skin only); El Abiad, 60 km SW Sebha, 18 (2 skin only; 

 2 skull only); 75 km W Ubari, 11; Meseguin 1; Umm el Araneb, 2; 

 6 km N Murzuch, 1; 55 km SSW Serdeles, 8; 20 km N Ghat, 1; 

 12 km N Ghat, 13 (4 skull only) ; Ghat, 25 (1 skeleton) ; El Gatrun, 17; 

 El Barcat, 4. 



Measurements. Averages and extremes of 12 adult males and 

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

 the type in brackets, are, respectively: Total length 211 (200-220), 

 210.7 (200-218), [213]; length of tail 121.6 (112-130), 124.3 (116-128), 

 [125]; length of hind foot 28.6 (28-30), 28.3 (27-29), [29]; length of 

 ear 13.4 (13-14), 13.2 (12-14), [13]; occipitonasal length of skull 

 28.3 (27-28.9), 27.9 (27.1-29), [28.4]; length of auditory bulla 10.5 

 (10.l-10.7j, 10.3 (10-10.7), [10.6]; crown length of molariform tooth- 

 row 3.6 (3.5-3.8), 3.6 (3.5-3.6), [3.6] ; greatest breadth across zygomatic 

 arches 15.4 (15.2-15.6), 14.6 (14.5-14.8), [15.6]; least interorbital 

 breadth 5.7 (5.2-6), 5.7 (5.5-5.8), [5.5]; breadth of rostrum at level of 

 antorbital foramina 3.1 (2.9-3.3), 3 (2.9-3), [3]; greatest length of 

 nasals 10.6 (10.2-11.1), 10.3 (9.8-10.6), [10.5]. 



Diagnosis. Upperparts Clay Color, suffused throughout with 

 brownish hairs imparting a streaked or marbled appearance; sub- 

 auricular patch prominent and Cinnamon-Buff; pinna of ear sparsely 

 haired and Clay Color; preauricular patch Pinkish Buff and extending 

 as a row of fine hairs onto anterior margin of pinna; postauricular 

 patch, circumorbital, rostral and mystacial areas, dorsal surfaces 

 of fore and hind feet and entire underparts white (in some specimens, 

 the venter is Pale Pinkish Buff owing to artificial staining) ; fore and 

 hind feet with five digits, each bearing a claw; tail distinctly bicolored 

 Cinnamon-Buff dosally, Light Buff ventraUy and terminating in a 

 prominent pencil, Avellaneous dorsally and Light Buff ventrally; 

 vibrissae short and composed of both brownish and whitish hairs. 

 Skull: Medium in size; braincase moderately arched; auditory 

 bullae relatively large and inflated: anterior palatine foramina and 

 posterior palatine canals narrow; zygomata moderately heavy and 

 convergent anteriorly; posterior lacerated foramina between basioc- 

 cipital and anteromedial margins of auditory bullae reduced to 

 slitlike aperatures. 



