Three new species of virgulate xiphidiocercariae infecting the freshwater snails of Kerala

Abstract

Three new species of virgulate xiphidiocercariae infecting the freshwater snails of Malabar, Kerala is described. Cercaria sp. XXVI Malabar n. sp. recovered from Bellamya bengalensis collected from Malappuram district of Kerala is characterized by an elongate-oval, spinose body and a highly contractile and spinose tail; dagger-shaped stylet with reinforced walls; coma-shaped virgula organ; muscular pharynx; short, narrow oesophagus; three pairs of penetration glands; bean-shaped excretory bladder and 12 pairs of flame cells. Cercaria sp. XXVII Malabar n. sp. recovered from Thiara tuberculata collected from Wayanad district of Kerala has a round to elongate-oval, spinose body; a highly contractile, spinose tail; dagger-shaped stylet; muscular pharynx; short oesophagus; narrow caeca extending up to ventral sucker; three pairs of penetration glands; bicornuate, thin-walled excretory bladder, and 12 pairs of flame cells. Cercaria sp. XXVII Malabar n. sp. infecting Paracrostoma huegelii also collected from Wayanad district, Kerala is characterized by elongate-oval, spinose body; contractile and spinose tail; dagger-shaped, inwardly curved stylet; virgula organ with elongated lobes; globular pharynx; three pairs of penetration glands; bicornuate, transversely elongate excretory bladder and 18 pairs of flame cells. All the three cercariae developed in sporocysts within the heapatopancreatic tissues of their respective snail hosts. The cercariae were compared with related species to establish their systematic position.