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U.S. NATIONAL MUSEUM BULLETIN 2 75 



Figure 16. — Distribution of the subspecies of Gerbillus aureus. 



specimens. In the present study specimens are available from more 

 localities and the systematic position of these gerbils can be more 

 accurately determined. It is now known that these subspecies actually 

 represent populations of a new species (Gerbillus aureus) which can be 

 distinguished readily from G. pyramidum, by its smaller size, conspic- 

 uously less tufted tail, and darker dorsal color. The name aureus, 

 because of page priority, is elevated to specific rank and favillus 

 becomes a subspecies of the new species thus formed. In addition, a 

 new subspecies, Gerbillus aurt us nalutensis, is being described from 

 northwestern Tripolitania. The validity of this species (G. aureus) 

 is further strengthened by the absence of any intergradation with G. 

 pyramidum. Setzer (195G) also recognized no intergfades between 

 aureus and favillus and gerbils representing G. pyramidum tarabuli, 

 whose range is to the south. 



This new species is the only species of gerbil known to inhabit 

 northwestern Tripolitania. The nearest populations of Gerbillus gerbil- 

 lus and G. pyramidum occur much farther south in the northern confines 

 of the Ha mad a el Hamra. To the east, in the vicinity of Sirte, G. 

 aureus favillus occurs sympatrically with G. pyramidum and G. eatoni. 



