Two East African species, A. lepidtun and R. pravus are espe- 

 cially interesting in that they~are typical of the Kapoeta Area 

 (Figure 328) and extend to Torit but little if any further west 

 into Equatoria Province. The reduced rainfall and consequent mod- 

 ification of vegetation in the Kapoeta Area has already been noted 

 (pages 836,838,839). R. pravus is unknown elsewhere in the Sudan; 

 A. lepidum does spill over via the Eastern Floodplain to the Cen_ 

 tral Mainlands where it is often common. A. lepidum is a species 

 strictly confined to E^st African areas wiTh reduced rainfall while 

 R. pravus , though n>ost common in the same areas, has a number of 

 restricted outlying populations in southern and western Africa. 

 It is therefore noteworthy that A. lepidum appears to be more 

 aggressive in its Sudanese distribution than R. pravus . Reasons 

 for these differences should be sought among the various factors 

 noted for uneven tick distribution (pages 8^5 to 8^8) . 



A. cohaerens , a strictly East African species that reaches 

 its western limits in eastern Belgian Congo, is also knovm in the 

 Siidan chiefly from the Kapoeta Area and questionably from adjacent 

 parts of the Torit Area. H. bequaerti of Torit and Raga_Loka Areas 

 is confined to East Africa except for a single known population in 

 western Sudan; this tick belongs to a group of hyrax parasitizing 

 species not known otherwise to occur in V/est Africa. R. append icu - 

 latus , on the other hand, is chiefly an East African species, but 

 in the Sudan occurs only in the Imatong forests and a small corner 

 of the Raga-Loka Area, where it is common. R. append i c ul atus re- 

 quires a more humid environment than many East African species and 

 is therefore absent in most East African areas of the Sudan. Popu- 

 lations of this tick also occur in the highlands of Central and 

 southeastern Africa, probably in part due to movements of cattle. 



East African components typical of arid areas not infrequent- 

 ly extend their range into the Southwest Arid District (south- 

 western Union of South Africa, Ovamboland, Angola). An example 

 of this pattern is A. brurapt i . The ability of this species to 

 reach and sxorvive in dry niches such as hyrax dens in otherwise 

 hiimid areas may account for its wide distribution and presence 

 in areas that appear unsuitable for its survival. Although A. 

 brumpti thrives and is best known from dry areas, its range of 

 humidity toleration may be more extensive than presently realized. 

 The general outline of the distribution of 0. savignyi in Africa 

 is somewhat similar to that of A. brumpti. 



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