Abstract
Monogenea is one of the most species-rich groups of parasitic flatworms worldwide with many species described from African freshwater fish. Little is known about the diversity and geographic distribution of monogenean parasites infesting the Red Sea fishes in Egypt. In the present study, a total of 45 specimens of the brushtooth lizardfish Saurida undosquamis (family: Synodontidae) and 35 specimens of the red porgy seabream Pagrus pagrus (family: Sparidae) was examined for monogenean infestation. Samples were collected from water locations at Hurghada coasts along the Red Sea in Egypt. Two different species were recovered. The first recorded parasite was Diclidophora merlangi infesting the lizardfish. This parasite was morphologically similar to the original description for the general body shape, size, shape and arrangement of the clamps and reproduction organs and the number of spines in the lateral groups of the genital atrium, but is distinguished in the host fish which is of a different genus. The second species was Loxuroides pricei. The morphological and quantitative data of the isolated specimens and the potential reproductive consequences supported their assignment to L. pricei than to the other congeneric species. This parasite can be separated from the morphologically similar L. sasikala through having a shorter distance from the anterior extremity to genital atrium or vaginal region, fewer testes and a slightly greater number of spines on cirrus and genital atrium. The two species represented new host and locality records from the Red Sea in Egypt.