RODENTS OF LIBYA 163 



Key to the Jirds (Meriones) of Libya 



1. Suprameatal triangle large and not enclosed posteriorly by enveloping processes 



of temporal and snpraoccipital bones; mastoidal portion of auditory bulla 

 conspicuously inflated posteriorly and projecting markedly beyond level of 



occiput M. crassus 



Suprameatal triangle small and enclosed posteriorly by enveloping processes of 

 temporal and supraoccipital bones; mastoidal portion of auditory bulla not 

 conspicuously inflated posteriorly and projecting only slightly beyond level 

 of occiput 2 



2. External meatal process of auditory bulla markedly inflated and adnate to 



squamous portion of temporal bone; suprameatal triangle completely en- 

 closed by enveloping processes of the temporal and supraoccipital bones; 



tail relatively long and prominently tufted M. caudatus 



External meatal process of auditory bulla not markedly inflated and clearly 

 distinct from squamous portion of temporal bone; suprameatal triangle 

 imperfectly enclosed by enveloping processes of the temporal and supra- 

 occipital bones; tail relatively short and without prominent tuft. 



M. libycus 

 Meriones caudatus Thomas 



Meriones libycus caudatus Thomas, Ann. Mag. Nat. Hist., ser. 9, vol. 3, p. 267, 

 March 191'.) (Tamari-Fergian, Tripolitania, Libya). 



General distribution of species. Currently known only from 

 Libya, but range probably includes other portions of North Africa 

 and adjacent Southwest Asia. 



Distribution in Libya. Widespread throughout the desert areas of 

 Tripolitania and the Fezzan. In Cyrenaica, this species is known only 

 from the coastal plain and the hamadas surrounding the oasis of 

 Giarabub. 



Distribution of the subspecies in Libya. 



Meriones caudatus amplus. Fezzan: Oases of Murzuch, Traghen, 

 Meseguin, El Gatrun, and intervening wadis and hamadas. 



Meriones caudatus caudatus. Tripolitania: Coastal plain and in- 

 terior deserts north of the Hamada de Tinrhert and Gebel es Soda. 



Meriones caudatus confalonierii. Cyrenaica and Tripolitania: 

 Coastal plain and littoral deserts adjoining the Gulf of Sirte. 



Meriones caudatus luridus. Cyrenaica: Coastal areas of northern 

 Cyrenaica and the inland hamadas as far south as Giarabub Oasis. 



Published records in Libya. Cyrenaica: El Agheila (de Beaux 

 [Meriones libycus confalonierii], 1932); El Agheila (Meriones libycus 

 confalonierii), Giarabub (Meriones libycus caudatus) (Toschi, 1951). 

 Tripolitania: Ain Hammam and Tamari-Faradie (Toschi [Meriones 

 schousboei], 1951). 



Comparisons. This species differs from Meriones libycus as follows: 

 Tail longer, with more prominent pencil, and black rather than brown; 

 auditory bullae noticeably larger and more inflated ventrally and 

 laterally; lateral meatal process of auditory bulla markedly expanded 



