The known Sudanese tick fauna comprises 62 identifiable spe- 

 cies plus two additional subspecies. It is conservatively esti- 

 mated that twelve to fifteen additional species remain to be dis- 

 covered here and that when a future count is made the presently 

 unknown components of the fauna will include approximately equal 

 numbers of northern, eastern, and western species. Of the 64. 

 known forms, ten are either Palaearctic in origin or are tenta- 

 tively referred to this Region, one is an introduced American 

 (Neotropical) species, and 53 are Ethiopian. 



Palaearctic Species 



H. dromedarii A. persicus 



15. excavalum" I. reflexus 



1. impeltatum '?0. savipyi 



■fl. detritum ?"T. s. simplex 



^. marginatum ^ vespertilionis 



The hyalommas are Palaearctic in origin and distribution al- 

 thovigh they invade a narrow vegetated northern fringe of the 

 Ethiopian Region. H. impeltatum has also gained fairly extensive 

 foothold in the savannahs of West Africa. The first three spe- 

 cies listed above conceivably could have reached the far flung 

 areas where they do exist even without the assistance of domestic 

 animals although there is little doubt that these vehicles have 

 greatly facilitated their spread. Details of the distribution 

 of H. detritum and H. marginatum in the Sudan and elsewhere out- 

 side ot the Palaearctic Region in Africa are vague. 



I. vespertilionis and A. persicus probably should be treated 

 as P^aearctic species that"have been able to establish themselves 

 as far south as the Cape through bat and human agencies. 



Consideration of 0. savignyi , A. reflexus , and I. s. simplex 

 as Palaearctic species"is entirely tentative. The xerophilic 

 tampan ranges from India to Southwest Africa and its distribution 

 has probably been influenced by cominon association with camels, 

 except in southern Africa where other factors must be considered. 

 savic-nyi in the Sudan is confined strictly to arid areas. The 

 ^^ t parasit e I. s. simplex is known only from a few, scattered 

 Oriental, Pallea?ctic, and Ethiopian records that defy zoogeograptu 

 ical evaluation. The pigeon parasite A. reflexus , probably Palaa. 



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