Light microscopically study of three helminth parasites infecting Raja batis Linnaeus, 1758 (Elasmobranchii:Rajiidae) recorded in the Red Sea, Egypt

When a dissection made to three specimens of skate Raja batis Linnaeus, 1758 flattened cartilaginous fishes bought randomly from the Red Sea city markets, were found naturally infected with three specimens of helminth parasites two species of digenea Monorchismonorchis Stossich, 1890, Lecithochiriumpriacanthi Yamaguti (1953) and one of tetrabothridea Echeneibothriumminutum Williams, 1966 impeded in spiral valve wall. The morphology and morphometric characterization were carried out by light microscopy. Species were recorded for the first time from Rajidae specimen in a new locality Red sea, Egypt. The present Monorchis species is characterized by its smaller size, smaller ovary; testes tandem and vitellaria are in the form of two lateral groups, near the caeca bifurcation, and the numbers of follicles vary from 7-9 on the right side and 7-11 on the left side. Lecithochiriumpriacanthi characterized by elongated slender body with acetabulum larger than oral sucker and tapered conical anteriorwith bluntposterior ends, supplied with a very short retracted short tail (ecsoma)end and two opposite small oval testes. This species is unique by two compact masses, 6-7 ovals to digitiform lobes vitellaria just posterior to ovary. Echeneibothriumminutum Williams, 1966 has very special features as acraspedote, euapolytic, Scolex consists of the head proper and a cephalic peduncle, the head bears the dorsal and ventral bothridia each of which is oval, flattened, andloculi arranged in 12–14 rows.