African cichlids are model systems for evolutionary studies and for host-parasite interactions, because of
their adaptive radiations and because they harbour many species of monogenean parasites with high host-specificity.
Here, we sampled five locations in southern Lake Victoria, the youngest of the African Great Lakes. We surveyed gillinfecting monogeneans from 18 cichlid species belonging to the Lake Victoria radiation superflock and two cichlid
species representing two older and distantly related lineages. We found one species of Gyrodactylus (Gyrodactylidae,
Monogenea), Gyrodactylus sturmbaueri Vanhove, Snoeks, Volckaert & Huyse, 2011, and seven species of
Cichlidogyrus (Dactylogyridae, Monogenea). Four species are herein described: Cichlidogyrus pseudodossoui n. sp., C.
nyanza n. sp., C. furu n. sp., C. vetusmolendarius n. sp.. Another species is reported but not formally described (because
of few specimens and morphological similarity with C. furu n. sp.). Two other species are redescribed: Cichlidogyrus
bifurcatus Paperna, 1960 and C. longipenis Paperna & Thurston, 1969. Our results confirm that the monogenean fauna
of Victorian littoral cichlids displays lower species richness and lower host-specificity than that of Lake Tanganyika
littoral cichlids. In C. furu n. sp., hooks V are clearly longer than the other hooks, highlighting the need to re-evaluate
the current classification system of haptoral configurations that considers hook pairs III-VII as rather uniform. Some
morphological features of C. bifurcatus, C. longipenis and C. nyanza n. sp. suggest that these are closely related to other
congeners that infect haplochromines. We also found morphological indications that representatives of Cichlidogyrus
colonised Lake Victoria haplochromines or their ancestors at least twice, which is in line with the Lake Victoria
superflock being colonized by two cichlid tribes (Haplochromini and Oreochromini).