Review of the African fish Louse genus Dolops (Branchiura)

The Aquatic Parasitology Research Group has been doing research on parasites in the Okavango Delta and Panhandle since 1997. Representatives of the Branchiura are present on several different fish hosts in the Delta and Panhandle. Dolops ranarum (Stuhlman, 1891) is a branchiuran that has a Pan-African distribution. In contrast with the other branchiurans present in Africa; Argulus (Müller, 1785) has 32 species and Chonopeltis (Thiele, 1900) has 14 species present in freshwater habitats in Africa, D. ranarum has only one representative in freshwater habitats on the continent. This leads to the question whether there may have been a speciation event in which new species may have developed. This study investigates the possibility of a speciation event using both morphological and molecular methods. Specimens were collected from different fish host genera such as Clarias Scopoli, 1777, Serranocromis Regan, 1920, Oreochromis Günther, 1889, Synodontis and Tilapia A. Smith, 1840, as well as Schilbe intermedius Rüppel, 1832 and Hepsetus odoe (Bloch, 1794). Subesquently, the fish lice were visually examined for characters that indicated significant differences. Specimens were also utilised for DNA sequencing. It was clear from the morphological results that there has been no speciation event as a result of the utilisation of different hosts. However, the molecular analysis was less successful, possibly due to the low quality of DNA as a result of the storage method.