30 U.S. NATIONAL MUSEUM BULLETIN 275 



In Libya, this species is known only from a few specimens from El 

 Agheila and Gheminez on the Cyrenaican coastal plain; therefore, 

 its taxonomic status is not well established. 



Subspecies confined to the Libyan coastal areas representing 

 populations on the periphery of the ranges of their respective species 

 are: Gerbillns campestris wassifi; Meriones caudatus confalonierii; 

 Eliomys qiiercinus cyrenaicus; and Jaculus desertifavillus. 



Because of the encroachment of the Saharan steppe onto portions 

 of the coastal plain, some subspecies, which typically inhabit the 

 Saharan Steppe Faunal Area, occur marginally in the Coastal Plain 

 Province. Chief among these intrusions from the steppe regions are 

 representatives of the following subspecies : Gerbillns campestris 

 dodsoni; Gerbillns gerbillns psammophilons; Gerbillns pyramidnm 

 hamadensis; Pachyuromys dnprasi natronensis; Meriones caudatus 

 luridus; and Jaculus jaculus whitchurchi. 



Conversely, members of typical coastal subspecies penetrate short 

 distances into the Saharan Steppe Faunal Area. Examples of coastal 

 subspecies which are found occasionally along the northern margins of 

 the steppe region are: Gerbillns ealoni eatoni; Gerbillns henleyi henleyi; 

 Meriones libycus auratus; Spalax ehrenbergi aegyptiacns; and Jaculus 

 deserti javillus. 



From the above examples, it is apparent that elements of two 

 different faunal aieas overlap in some parts of coastal Libya. 



Distributions of the porcupine (Hystrix cristata), the large Egyptian 

 jerboa (Jaculus orientalis), and the small gerbil (Gerbillns kaiseri) 

 do not conform to other distributional patterns of rodents in Libya. 

 All three are known from both the Cyrenaican Plateau and the Gebel 

 Nefusa, which belong, respectively, to provinces of the Mediterranean 

 and Saharan Steppe Faunal Areas. Such a discontinuous distribution 

 for members of the same species strongly opposes modern concepts 

 of speciation. It is most likely, therefore, that the populations of 

 J. orientalis and G. kaiseri on the Gebel Nefusa are relicts of formerly 

 continuous populations. The porcupine, owing to its reputed adapta- 

 bility and tenacity, represents a genetically plastic species which 

 has been affected less by ecologic and climatic barriers and thus has 

 not followed the distributional patterns of other Libyan rodents. 



Saharan Steppe Faunal Area 



The Saharan Steppe Faunal Area comprises the steppe region of 

 Libya located between the inner margins of the coastal plain and the 

 Saharan interior; it is situated between the Mediterranean Faunal 

 Area and the Saharan Faunal Area. The Saharan Steppe Faunal Area 

 is divisible into two distributional provinces, the Transitional Desert 

 Province and the Tripolitanian Gebel Province. The Transitional 



