RODENTS OF LIBYA 47 



p. 280). These fossil voles from Cyrenaica and a fossil Ellobius Fischer 

 from the Pleistocene deposits in Algeria and Tunisia constitute the 

 only known fossil records of the Microtinae in Africa. Members of the 

 genus Ellobius are now restricted to Eurasia, but in Cyrenaica, a 

 modern vole (Microtus mustersi) has persisted into modern times. 

 According to Bate, this Pleistocene vole, which is known from 63 

 specimens consisting of teeth and fragments of jaws, differs from the 

 modern Microtus mustersi primarily in having shorter and narrower 

 cheek teeth with smaller reentrant angles. Bate concluded that M. 

 cyrenae belongs to the Microtus guentheri group, which also includes 

 Microtus mustersi and M. philistinus of Palestine. 



According to Bate, the remains of voles were distributed through 

 four successive levels of the Hagfet ed Dabba Cave, which would 

 indicate an occupation of considerable duration in Cyrenaica and 

 suggests an early Pleistocene arrival of voles into Cyrenaica. 



This discovery of fossil voles in Cyrenaica, coupled with the present 

 distribution of members of the M. guentheri group in the Middle 

 Eastern countries, supports my hypothesis (and also that of Bate) 

 that much of the Eurasiatic fauna of North Africa entered by way of 

 the eastern Mediterranean countries and the Isthmus of Sinai some- 

 time during the Pleistocene. 



Probably the most unequivocal example of a Pleistocene relict is the 

 vole, Microtus mustersi, of the Cyrenaican Plateau and adjacent coastal 

 plain. These Libyan voles are the only living representatives of the 

 subfamily Microtinae on the African continent and clearly represent a 

 marginal intrusion of the Eurasian rodent fauna into North Africa. 

 Today the nearest populations of Microtus occur in the Middle East 

 and in Turkey. During the pluvials, suitable moist habitats probably 

 were continuous along the coastal areas of northern Egypt, thus facili- 

 tating the dispersal of voles. Apparently, owing to the return of arid 

 conditions during the following interpluvial period, the coastal areas 

 of Egypt became dry, as they are today, and no longer afforded suit- 

 able habitats. 



The Cyrenaican Plateau, by virtue of its higher elevation and more 

 mesic habitats, must have served as a refugium for voles throughout 

 the arid interpluvial periods. With the gradual return of less arid 

 conditions to North Africa and Cyrenaica, voles reentered the Libyan 

 coastal plain, while the Egyptian coastal plain still remains dry and 

 unfit for them. 



In addition to fossil rodents, several other genera of fossil mammals 

 were discovered in these Pleistocene deposits of northern Cyrenaica. 

 These include Crocidura Wagler, Vulpes Oken, Panthera Oken, Bos 

 Linnaeus, Ammotragus Blyth, Gazella Blainville, Hippotigris Smith, 

 and Rhinoceros Linnaeus. Of these genera, only the shrew (Crocidura) 

 and the fox (Vulpes) are found in the region today, and they are con- 



