Morphotaxometry and Ultratopography of Lytocestus haryanii n.sp. (Caryophyllidea: Lytocestidae) from the intestine of freshwater catfish Clarias batrachus Linnaeus 1758 (Siluriformes: Clariidae) of river Yamuna, Yamuna Nagar, Haryana, India

Abstract

The present investigation deals with the first report of newer species of caryophyllid cestodes, Lytocestus haryanii n.sp. (Caryophyllidea: Lytocestidae) in the freshwater catfish, Clarias batrachus Linnaeus 1758 (Siluriformes: Clariidae) of river Yamuna from Yamuna Nagar, Haryana, India from July 2018 to June 2020. These helminthes are the most common cestodes (endoparasites) among the fishes of fresh water, brackish water, and marine habitat worldwide. The recovered newer worms were processed through the standardized protocol for the microscopic observations and morphometry, ultratopographic study through scanning electron microscopy, and anatomical analysis by histology using microtomy techniques followed by the double staining. The findings of the present worms were substantiated and compared with the earlier reported species of the same genera from different hosts shared the common group using advanced numerical taxonomy for the taxometric validation. The present proposed newer worms shared all the common characteristics which helped in the generic diagnosis and are closely related to the species collected from the same host species inhabiting different freshwater bodies. The worms comprised several striking contrasts in the combination of distinguishing characters of taxonomic significance in special reference to shape, size, orientation, distribution, and the dimension of the body (single proglottid), scolex, neck, testes, ovary, cirrus pouch, vitellaria, eggs, and excretory pore. Based on the striking morphological, taxometric, ultratopgraphic, and histological differences summarized here can, therefore, be used to propose the worm as a new species.