RESUMEN

The life cycle of Pleurogenoides wayanadensis Shinad & Prasadan, 2018, infecting the frogs Hoplobatrachus tigerinus and Euphlyctis cyanophlyctis, is elucidated in this study. All the life cycle stages from egg to egg-producing adults were elucidated under natural conditions and successfully established in the laboratory. The life cycle took about 58 to 65 days for completion. Miracidia were released by teasing the eggs with fine needles. Sporocysts were found in the freshwater snail, Bithynia (Digoniostoma) pulchella, collected from paddy fields at Payode, Western Ghats, Wayanad region, in the months of October and November 2019. Cercariae were of the virgulate xiphidiocercous type. Metacercariae were recovered from the eyes of the damselfly naiads of the species Ischnura sp. and Copera sp., and the thorax and abdomen of the dragonfly naiads, Orthetrum sp. The metacercariae showed progenetic development. The growth and development of the metacercariae in the naiads that were exposed to cercariae, and development of the trematode in frogs that were force-fed with encysted metacercariae, have been studied at regular intervals. The prepatent period is 14-19 days. The present life cycle study of a Pleurogenoides spp. forms the seventh report from the world, fourth report from India and the third from Kerala.

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RESUMEN

Two cercariae were recorded from freshwater snails, one each from Digoniostoma pulchella and Indoplanorbis exustus and named Cercaria sp. III Western Ghats n.sp. and Cercaria sp. IV Western Ghats n.sp. respectively. Cercaria sp. III Western Ghats n.sp. is distome, ocellate and pharyngeate with peculiar spines on the tail, belongs to the Parapleurolophocerca group. This cercaria has 10 pairs of penetration glands in two groups; thick walled large excretory bladder and 10 pairs of flame cells including a pair arising from the caudal excretory canal. Cercaria sp. III Western Ghats n.sp develops inside the sausage shaped redia. Developed cercariae were found outside the rediae, in the host tissue. The furcocercous cercaria, Cercaria sp. IV Western Ghats n.sp is elongate, non ocellate, pharyngeate and longifurcocercous with three crowns of spines beside mouth, three pairs of penetration glands, small excretory bladder and twenty-two flame cells including four flame cells in the tail stem. Asexual multiplication of the organism occurs inside the sporocyst in the hepatopancreas of I. exustus. The present paper reports two new cercariae with their intra-molluscan stages recovered from the snails of the Wayanad region of the Western Ghats, and their morphological and morphometric comparison with the related species to determine their systematic positions.

RESUMEN

Two new furcocercous cercariae, Cercaria sp. I Western Ghats n. sp. and Cercaria sp. II Western Ghats n. sp. were found infecting the freshwater snails Indoplanorbis exustus and Thiara tuberculata respectively of the Wayanad region of the Western Ghats. Cercaria sp. I Western Ghats n. sp., a distome, apharyngeate, non-ocellate and spinose cercaria having three pairs of penetration glands, kidney- shaped small caeca and 20 pairs of flame cells including a pair in the furcae was recovered from I. exustus and Cercaria sp. II Western Ghats n. sp., a non-ocellate, pharyngeate, longifurcate furcocercous cercaria with two pairs of irregularly bordered penetration glands, septate caeca and 21 pairs of flame cells including three pairs in the furcae, from T. tuberculata. Sporocysts of Cercaria sp. I Western Ghats n. sp. were sausage-shaped while that of Cercaria sp. II Western Ghats n. sp. were thread-like and both of them developed in the hepatopancreas of their hosts. This paper describes the two new cercariae with their intramolluscan stages and compares them with related species to establish their systematic positions.