Description of a new species of Dermoergasilus Ho & Do, 1982 (Copepoda: Ergasilidae) from the redbelly tilapia Coptodon zillii (Gervais) (Perciformes: Cichlidae) in Basrah, southern Iraq

摘要

A new species of Dermoergasilus Ho & Do, 1982 (Copepoda: Ergasilidae) parasitic on the gills of the redbelly tilapia Coptodon zillii (Gervais) from Basrah, southern Iraq, is described. Dermoergasilus cichlidus n. sp. is morphologically similar to D. longiabdominalis El-Rashidy & Boxshall, 2001 in the body length to width ratio, the swimming legs armature, the shape of the urosome and the small slightly spiniform seta on the exopodal segment of leg 5. However, the main differences are the presence of long setae on the endopod of leg 1 in D. cichlidus n. sp. (vs relatively short setae); the inner apical spine on the tip of the endopod of leg 1 being only slightly longer than the outer apical spine (vs inner apical spine about twice as long as the outer); the first interpodal sternite ornamented with spinules (vs interpodal sternites not ornamented); and the caudal rami and anal somite of equal length (vs caudal rami length c.2/3 of the length of the anal somite). Dermoergasilus occidentalis can be distinguished from D. cichlidus n. sp. by the relative length of the antennal segments, the absence of a minute terminal spine on the digital process of the caudal ramus and by differences in the mouth parts.