Description of a New Species of Dermoergasilus planilizai sp. nov. (Copepoda: Ergasilidae) from abu Mullet Planiliza abu (Heckel) Gills at Al-Gharraf River, Southern Iraq.

Dermoergasilus planilizai sp. nov. is described from the gills of the abu mullet Planiliza abu (Heckel), the only freshwater member of the Mugilidae occurring in the Mesopotamian region. Specimens were collected from the Al-Gharraf River, southern Iraq. The new species is distinguished from its closest congener, Dermoergasilus varicoleus [13]; by the following combination of characters: (i) setae on caudal rami distinctly longer than the digitiform process (vs. shorter); (ii) terminal spines on endopod of leg 1 strongly curved (vs. straight); and (iii) free segment of leg 5 approximately three times longer than the basal segment (vs. twice as long). (iv) Further separation is supported by antennal proportions; the second and third endopodal segments together of the antenna equal to 41.6% in D. planilizai sp. nov. (vs. 60% in D. varicoleus).