Parasites of South African freshwater fish. III. Rhabdochona (Rhabdochona) versterae n. sp. (Nematoda: Rhabdochonidae) from the spot-tailed robber, Alestes imberi Peters 1852.

A new species of Rhabdochona was recovered from the spot-tailed robber, Alestes imberi Peters 1852 in the Sabie River, Kruger National Park. It differs from its nearest relative, Rhabdochona moraveci Puylaert 1973 in that it has shorter spicules and fewer prostomal teeth. The new species also shows affinities with Rhabdochona paski Baylis 1928 and Rhabdochona congolensis Campana-Rouget 1961, but differs from the first-named species in that it has shorter spicules and fewer precloacal papillae. It differs from the last-named species in the number and arrangement of the labial and cephalic papillae, and the absence of finger-like processes on the tip of the female tail. The subgenus Rhabdochona Moravec 1972 is characterized by the absence of filaments or floats on the mature eggs. These structures are also lacking in the new species, which is therefore described here as Rhabdochona (Rhabdochona) versterae n. sp.