Morphological and molecular analyses of Tylodelphys spp. metacercaria (Trematoda: Diplostomidae) from the vitreous humour of two freshwater fish species, Channa gachua (Ham.) and Puntius sophore (Ham.).

Trematodes of family Diplostomatidae consists of a large and diverse group of parasites which have larval stages that are very important pathogens of wild and cultured freshwater fishes worldwide, can cause serious impacts. Our understanding of the diplostomids diversity, though, remains deficient and limited especially in India. In the present study, the morphology and molecular characterization of Tylodelphys spp. from the vitreous humour of eye, collected from two economically important food fish, dwarf snakehead Channa gachua (Perciformes: Channidae) and pool barb Puntius sophore (Cypriniformes: Cyprinidae) were described from Bijnor and Meerut, Uttar Pradesh (U.P.), India respectively. Tylodelphys spp. were characterized morphologically by light microscopy and SEM observations. Partial sequences of the ribosomal ITS1-5.8S-ITS2 gene cluster were also used for molecular identification of the species. Combined morphological and molecular analyses revealed the presence of three species of Tylodelphys: Tylodelphys sp. CG from C. gachua and Tylodelphys sp. PS 1, Tylodelphys sp. PS 2 from P. sophore respectively. This study demonstrated that molecular diversity of Tylodelphys spp. in Meerut, UP, India that may contribute to our knowledge of the diagnosis and taxonomy of diplostomids in fish.