Ecological morphotaxometry of trematodes of garfish (Teleostomi: Belonidae) from Gangetic riverine ecosystem in India. I. Morphology and taxometric assessment of Cephalogonimus yamunii n.sp.

A new endoparasitic fluke, Cephalogonimus yamunii n.sp. is described from the intestine of freshwater fish Xenentodon cancilla (Belonidae). The worms could be differentiated from C. amphiumae (Chandler 1932), C. apognichthysi (Gupta and Puri 1982), C. hanumanthai (Agrawal and Agarwal 1984), C. salamandrus (Dronen and Lang 1974), C. simhai (Singh 2010) and C. vesicaudus (Nickerson 1912) in a unipartite seminal vesicle, genital pore subterminal anteriorly, opening at the hind end of oral sucker, equatorial or sub-equatorial testes, besides other morphological attributes of shorter body and pharynx, larger oesophagus and oral sucker, smaller ventral sucker, testes, cirrus sac and ovary, and a terminal excretory pore. Taxometric substantiation has been presented by using Polythetic Divisive Classificatory System, and ecological attributes have been evaluated to validate specific distribution patterns in population dynamics of the new species in simultaneous contributions.