SCANNING ELECTRON MICROSCOPIC STUDY ON NEOECHINORHYNCHUS IRAQENSIS (ACANTHOCEPHALA: NEOECHINORHYNCHIDAE), A PARASITE OF MUGILID FISH PLANILIZA ABU (ACTINOPTERYGII: MUGILIDAE) FROM TIGRIS RIVER, IRAQ

Abstract

The species Neoechinorhynchus iraqensis occurs mostly in freshwater fishes in Iraq. The parasite is recovered from the intestine of Planiliza abu. The females specimens measure 25.0-71.8 mm in length, and the males measure 14.0-26.0 mm in length. The length of the proboscis measures 0.10-0.13 mm for both sexes. The reproductive system of male locates in the posterior third of the body and is formed of two elliptical testes. In the females, the uterine bell is longer than the uterus; its length measures 0.010-0.012 mm. The description is augmented by scanning electron microscope observations. The proboscis has three rings, each of six curved spine; the spines of the anterior ring are long (11.34-17.53 µm in length). The posterior ring spines are shorter than those of anterior ones (11.71-11.74 µm in length). The eggs are fusiform in shape (28.4-29.5 µm in length and 14.8-18.8 µm in width). The micropores are spread on the body surface measuring (0.23-1.32 µm in character). The body surface is devoid of spines and consists of pseudosegment. The tegument is characterized by lacunar system and muscular layers beneath, which cover the pseudocoel. In conclusion, the present study by using scanning electron microscope, many new features of N. iraqensis that were not possible to be monitored in the description based on the optical microscopy.