RODENTS OF LIBYA 223 



subspecies by its proportionately larger auditory bullae and generally 

 smaller size of most cranial and external measurements (Ellerman 

 and Morrison-Scott, 1951; and Toschi, 1951). At this time, com- 

 paratively few areas in Libya were represented by specimens, and 

 the above assignments were based largely on geographic occurrence 

 with little regard for taxonomic relationships. Zavattari (1934, p. 896) 

 recorded both J. j. deserti and J. j. jaculus from El Agheila on the 

 Cyrenaican Coast. The occurrence of these two subspecies in the 

 same geographic area clearly violates the concept of subspeciation. 

 Setzer (1957), the most recent worker in Libyan mammals, had no 

 specimens of the lesser jerboa available and accordingly was unable 

 to investigate this problem. In the present study, adequate series 

 are available from widely scattered localities and thus provide an 

 opportunity to clarify the taxonomic status of the small jerboas 

 of Libya. 



No topotypes of J. j. deserti are available for study, but Loche 

 (1867, pp. 100-101), in the original description, described this jerboa 

 as follows: "Head short, terminated by a small muzzle; eyes black 

 and shining, ears medium and taking their origin from a white patch; 

 pelage of the upper parts a pale dun color, slightly tinted with black 

 on the rump, resulting from the blackish tips of the otherwise dun- 

 colored hairs; hairs of the sides of the body and flanks white, ter- 

 minated by tawny and brownish hairs; face, outer parts of shoulders, 

 thighs and ventral surface of tail uniformly dun-colored; posterior 

 surfaces of hind limbs, pencil and plantar surfaces of the hind feet a 

 tawny-brownish color; upper eyelids, sides of the muzzle, all of the 

 front limbs, all underparts and inner surfaces of the hind feet are 

 white: a line of this same color extends ventrally along the tail to 

 the terminal brush, which is brown and white; nails white; total 

 length 310 mm., length of tail 170 mm." Loche (1867) indicated 

 that Dipus deserti (= Jaculus jaculus deserti) was a miniature repro- 

 duction of Dipus gerboa Olivier ( = Jaculus orientalis). 



Representatives of J. j. deserti from Biskra, Algeria, agree closely 

 with the above description and are found to differ from typical J. j. 

 jaculus in a number of additional characters, particularly in having 

 brownish rather than white hairs in the soles of the feet, much darker 

 dorsal color, and two foramina in the angular process of the lower jaw, 

 instead of one as in J. j. jaculus. Furthermore, in several localities in 

 Libya, jerboas of the deserti type and those typical of J. j. jaculus 

 occur sympatrically and show no evidences of interbreeding. The 

 present work indicates that J. j. deserti is sufficiently distinct to 

 warrant reinstatement as a full species, and because of priority (1867), 

 assumes precedence as the nominate form. The extralimital forms 

 Jaculus loftusi vocator Thomas, 1921 (type locality: Sohar, Muscat, 



