On Some Gastrocotyline (Monogenoidean) Parasites of Indian Clupeoid Fishes, Including Three New Genera

Abstract

Seven species of monogenetic trematodes, including the two genotypes, Engraulicola forcepopenis George, 1961 and Engrauliscobina thrissocles (Tripathi, 1959), are recorded. All seven of these atypical gastrocotylines belong to the subfamily Gastrocotylinae s.s. and are parasitic on clupeoid fishes. Four species in the present collection, viz., Engraulicola microph aryngella sp. n., Engraulixenus malabaricus gen. et sp. n., Engrauliphila grex gen. et sp. n., and Engrauliscobina triaptella sp. n., were collected from fishes of the family Engraulidae, while an entirely new type, Pellonicola elongata gen. et sp. n., was obtained from Clupeidae. The tendency to unilateral inhibition of the clamp rows is incomplete in all these atypical gastrocotylines, and all are characterised primarily by their clamp structure. Diagnostic characters, with special reference to the haptor (its adhesive units or clamps and anchors), the male terminalia, vaginal complex, and other salient features which appear to be taxonomically important, are given for each species.