During 1982-83 fish parasitological surveys were carried out in 15 dam reservoirs in the Transvaal. The fish ectoparasite Dolops ranarum was found on eight different fish species of which Oreochromis mossambicus. Clarias gariepinus and Barbus marequensis are regarded as main hosts. Distribution records and infestation statistics are presented. It was found that D.ranarum is restricted to the Limpopo Drainage System. An evaluation of site preference on host fish reveals that the mouth cavity, in the case of 0. mossambicus, and skin and fins, in the case of C . gariepinus, were the sites most intensively infested by this parasite.

Fertilization and hatching of D. ranarum eggs under laboratory conditions are described. The morphology of the newly hatched larvae was studied by scanning electron microscopy and the results are compared with existing knowledge.

The branchiuran ectoparasite Dolops ranarum (Stuhlmann, 1891) was described almost one hundred years ago. This descriptional though valid is incomplete. A redescription is given. New information was obtained with light and scanning electron microscopy. Morphometric values are included and a species diagnosis is presented.