DERMACENTOR 



INTRCDUCTION 



Dermacentor , a medically important genus in many parts of the 

 world, is represented by only three species in tropical Africa. 

 Small populations of two of these, D. c. circumguttatus and D, 

 rhinocerinus , occvtr in Equatoria arid Bahr El Ghazal Provinces of 

 the Sudan. In Africa they are always rather rare and largely con- 

 fined to the rhinoceros and elephant. As such, they are of little 

 more than academic interest. The identity of these species may be 

 determined easily from the following keys and illustrations. 



The third African species, D, hippo potamensis (Denny, 1843) 

 (= Ixodes bimaculatum Denny, 1843, and Amblyorama hippopotami Koch, 

 1844), W£is originally described from Hippopotamus amphibius of 

 South Africa, Schulze (1919) erected the genus Cosmiomma for this 

 species on the basis of its Hyalomma- like characters although it 

 lacks accessory shields and subanal shields. Zximpt (1951 ) sank 

 Cosmiomma under Dermacentor but Theiler states (correspondence) 

 that Schulze *s definition jtistifies its retention as a genus. 

 Other authors have placed it in Hyalomma . Still another study by 

 a qualified student on the original material appears necessary be- 

 fore an acceptable systematic niche can be found for D. (C.) hippo- 

 potamensis . "" 



D, (C.) hippo potamensis has been reported from South Africa 

 and between '•Zanzibar" (i.e. East Africa) and the Great Lakes (Tan- 

 ganyika). For over a century, the only positively known specimens 

 have been the types described by Denny and by Koch, which have been 

 seen again by later students. In the collections of the East Afri- 

 can Veterinary Organization there is a single male taken from vege- 

 tation at Manyani, Teita District, Kenya, 5 November 1951, D. L. 

 W, Sheldrick legit . This specimen, according to J. B. Walker (cor- 

 respondence), is almost exactly like the type material illustrated 

 by D'Snitz (1910B), One or two specimens are in the collection of 

 the Veterinary Department at Kabete, Kenya. 



D. (C.) hippo potamensis is a large, brightly colored Amblyomma- 

 like tick. The male scut tun is described as pale straw- yellow with 

 symmetrical black markings and a few small punctations; ventrally 



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