Two species of Rhabdochona Railliet, 1916 (Nematoda: Rhabdochonidae) parasitising cyprinid fishes in Iraq, with a redescription of R. tigridis Rahemo, 1978 (emend.)

Abstract

Two species of Rhabdochona Railliet, 1916 (Nematoda: Rhabdochonidae) were recorded from cyprinid fishes in the basin of the River Tigris, northern Iraq: adults of R. (R.) tigridis Rahemo, 1978 (emend.) from Capoeta trutta (Heckel) and Cyprinion macrostomum Heckel and fourth-stage larvae of R. (Globochona) sp. from C. macrostomum, Barbus barbulus Heckel and Barbus kersin Heckel. Light and scanning electron microscopical studies of this material made possible a detailed redescription of R. tigridis, which is characterised by 14 anterior prostomal teeth and filamented eggs. It differs from the most similar species, R. fortunatowi Dinnik, 1933, mainly in the presence of large deirids close to the prostom. R. grandipapillata Rahemo & Kasim, 1979 is considered a junior synonym of R. tigridis. Fourth-stage larvae of Rhabdochona (G.) sp., characterised by eight anterior prostomal teeth and the presence of caudal processes on the tail tip, represent the first record of a Rhabdochona species of the subgenus Globochona Moravec, 1972 in Iraq.