Taxonomical and phylogenetic characterizations of a new intestinal parasite Proenenterum myripristiae (Digenea, Lepocreadiidae) infecting Pinecone soldier fish Myripristismurdjan (Beryciformes, Holocentridae) from the Red Sea, Egypt

Members of superfamily Lepocreadioidea are of considerable interest biologically as they comprise important groups of worms in range of marine habitats. In the present study, morphological characterization of Proenenterum myripristiae (Family: Lepocreadiidae), a new digenetic trematode infecting the intestine of Pinecone soldierfish Myripristismurdjan, was described using light microscopy for the first time from Coasts of Red Sea at Hurghada City, Egypt. Fish samples were trapped alive during the period of August 2014–May 2015 and necropsied for any helminth parasites. Out of 50, examined fish specimens, only 16 (32.0%) were found to be naturally infected. The large-sized fish reaching ˃30 cm and ˃110 g were more intensively infected than the smaller ones. The present species has all the characteristic features of the genus Proenenterum and characterized by elongated body with anterior pointed and posterior broad ends, two well-developed muscular suckers with ventral larger than oral one, caeca united posteriorly to form cyclocoel, two lobed testes, cirrus sac largely pre-acetabular, lobed ovary, vitelline fields reach to the ventral sucker and excretory vesicle is I-shaped. The present species morphology resembles the previous recorded species from Beryciformes, but with less dimensions of different body parts. Molecular characterization based on 28S large subunit ribosomal DNA gene was done to confirm the obtained morphological and morphometric results. A preliminary genetic comparison between LSU rDNA of this parasite and other species of Lepocreadioidea places the present specimen as a putative sister taxon to P. ericotylum and P. isocotylum.