Gyrodactylus thlapi n. sp. (Monogenea) from Pseudocrenilabrus philander philander (Weber) (Cichlidae) in the Okavango Delta, Botswana.

A new species of Gyrodactylus von Nordmann, 1832 and the first monogenean reported from Botswana is described from the cichlid Pseudocrenilabrus philander philander, bringing the number of gyrodactylids described from the African Continent to 18. Gyrodactylus thlapi n. sp. can be readily discriminated from the other described species almost exclusively by the shape of its hamuli, which have short roots and large, elongate ventral bar attachment points with the dorsal bar attachment point, demarcating the junction between the hamulus shaft and the root, positioned at the anterior terminus of the attachment plane. The marginal hooks of G. thlapi n. sp., which most closely resemble those of G. groschafti Ergens, 1973, are compared and discussed.