A new species, Paradiplozoon ichthyoxanthon (Monogenea: Diplozoidae) is described from the gills of Labeobarbus aeneus (Cyprinidae) in the Vaal Dam and Vaal River Barrage in the Vaal River, South Africa. This species is the first in this genus from southern Africa; Paradiplozoon aegtyptense and Paradiplozoon ghanense have been described from northern Africa. The new species differs from all other Paradiplozoon species on the basis of the combination of morphological characteristics, namely disk-like haptor, eggs without filaments, clamp and central hook morphology and size of specimens. The species description is accompanied by a description of the reproductive organs. The internal transcribed spacer of the ribosomal gene (ITS2) was studied and the South African individuals formed a distinct clade, supporting the establishment of a new species.

Cichlidogyrus philander was originally described from Pseudocrenilabrus philander philander in Lake Kariba, Zimbabwe. Specimens from four fish species were collected during this study over a 14-month period from the Padda Dam, Johannesburg, transported to the laboratory and killed. Following examination, only P. p. philander was found to be infected with C. philanderindicating strict host specificity. Parasite intensity varied from 0 to 184 specimens per fish. Although no significant correlation between season and the infection of specimens of C. philander occurred, a maximum mean intensity of 91.6 occurred in winter. The prevalence was 100% in 10 of the 14 surveys, with no preference for host sex. Mean intensity of infection correlated positively with total length of the host and more parasites were present on fish with a higher condition factor. The distribution on the gill arches shows no significant difference between the number of parasites from gill arches on the left and right sides of fish. More parasites were present on the third and second gill arches, with the majority dorsally, on the distal ends. Water quality variables showed no correlation between prevalence, abundance or mean intensity of this parasite.

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