Two species of Rhabdochona (Nematoda: Rhabdochonidae) from the cyprinid fish Luciobarbus kersin (Heckel) in northern Iraq, including R. (Globochona) kurdistanensis sp. n.

A new nematode species, Rhabdochona (Globochona) kurdistanensis sp. n. (Rhabdochonidae), is decribed based on specimens collected from the intestine of the barbel Luciobarbus kersin (Heckel) (Cyprinidae) in the Greater Zab (type locality) and the Lesser Zab Rivers, Tigris River basin, Kurdistan Region, northern Iraq. It is mainly characterized by a prostom with 8 anterior teeth, the presence of basal prostomal teeth, bifurcated deirids, length ratio of the muscular and glandular portions of oesophagus (1:14.4-17.8), conspicuously short left spicule (180-204 microm), arrangement of genital papillae, nonfilamented eggs, and by having cuticular ornamentations on the tail tip (2 lateral denticular outgrowths in female and numerous fine spines in male). Description of a gravid female of Rhabdochona (Rhabdochona) sp. with 14 anterior prostomal teeth and filamented eggs, recorded from L. kersin of the Greater Zab River, is also provided. R. kurdistanensis sp. n. is the fifth valid species of Rhabdochona Railliet, 1916 and the only representative of the subgenus Globochona Moravec, 1972 recorded from Iraq.

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

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.