The trematode Skrjabinolecithum spasskii Belous, 1954 (Digenea: Haploporidae), a mullet parasite (Mugilidae) from Peter the great bay of the sea of Japan and from Vietnamese waters of the Gulf of Tonkin: Morphology and molecular data

Abstract

The trematode Skrjabinolecithum spasskii was described by Belous from a redlip mullet, Mugil soiuy (= Liza haematocheila ), that was caught in the Razdolnaya (Suifun) River (in the southern Far East of Russia). In the description of the species the author noted that the adult S. spasskii had no pigment eye spots; it had a spherical testis and short caeca; the uterus contained eggs with miracidia devoid of an eye spot. We found adult worms of this species in the intestine of the redlip mullet Liza haematocheila and the striped mullet Mugil cephalus from Peter the Great Bay of the Sea of Japan and in the striped mullet M. cephalus from northern waters of Vietnam in the Gulf of Tonkin. Our study of the morphology of S. spasskii showed that the worms have diffuse eye spots, V-shaped testis, long caeca that reach the level of the middle of the posterior third of the body, as well as a uterus with unembryonated eggs with an operculum on one pole and a knob on the other pole. The miracidium develops on eggs that hatch in water and has an eye spot. An analysis of the nucleotide sequences of the 28S rRNA gene and the ITS1-5.8S-ITS2 fragment revealed the intraspecific differentiation of three genotypes of S. spasskii ; two of these were detected in the trematodes from the Primorskii krai and one genotype was found in the trematodes from Vietnam.