RHIPICEPHALUS 



INTRODUCTION 



It appears well established that continental Africa is the 

 place of origin and center of distribution of Rhipicephalus ticks. 

 Of the 4-6 rhipicephalid species and subspecies that Zumpt (1950A) 

 recognized in his preliminary generic revision, 39 (including the 

 now cosmopolitan R. s. sanguineus ) are endemic in the Ethiopian 

 Fauna! Region; two are Oriental; and five range from southern 

 Europe and northern Africa into Russia. 



The genxos Rhipicephalus comprises almost a third of the known 

 Sudan tick fauna and contains more than twice as many endemic 

 African species as any other ixodid genus in the Ethiopian Faunal 

 Region. 



King (1926) listed five forms of Rhipicephalus from the S\i_ 

 dan. In addition, R. capensis has been apparently erroneously 

 referred to the Sudan ( Zumpt 19A2B). During the present study, 

 seventeen species and two additional subspecies, or nineteen 

 different forms, have been discovered in the Sudan. 



Zumpt *s (I95OA) major contribution in bringing together the 

 basic taxonomic data for this difficult genus id.ll facilitate 

 greatly the final revision of rhipicephalid species. Earlier, 

 Theiler (l9/i.7,1949B,1950A,B) had commenced study of individual 

 species, an effort that is still imderway (Theiler and Robinson 

 1953B, Theiler, Walker, and Wiley 1956). Very caref\il and thor- 

 ough studies are also in progress by Walker (1956), who has 

 severed further reports completed or in an advanced stage of 

 preparation. Since Zvimpt's classic preliminary work, Wilson 

 (1954) described a new species, R. hurti, from Kenya and Santos 

 Dias has provided a number of new names, the validity of which 

 are uncertain. Obviously, new criteria must be sought to sep- 

 arate many rhipicephalid species and subspecies. In an attempt 

 to apply characters surrounding the female genital aperture, 

 Feldman-Muhsam (1952A) has distinguished another species, R. 

 secundus, among populations appearing to be R. s. sanguineus . 

 However , problems of morphological and biological criteria for 

 this genus are not likely to be solved until more exhaustive 

 field research and patient laboratory investigation have been 

 devoted to them. 



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