Larval stages of digenetic trematodes ofMelanopsis praemorsa (L. 1758, Buccinum) (Thiaridae) snails from Yarmouk River, Jordan

Larval stages of digenetic trematodes in Melanopsis praemorsa snails from freshwater bodies in Palestine

“…This cercaria resembles that of Cercaria melanopsi V described previously from Melanopsis praemorsa snails collected from Yarmouk River, Jordan [15] , except that the number of pairs of penetration glands (4 vs 5) and the number of flame cells (14 vs 16) are different. It also resembles that of Sphaerostoma bramae which develops in a sporocyst in Bithynia tentaculata [19] .…”

“…Also Cercaria melanopsi palestinia II is different from Cercaria brevifurca which develops in Planorbis trivolvis as well as Cercaria cristata except that Cercaria brevifurca has four pairs of glands ventral to cecum and rami are not bearing fin-folds [23] . Cercaria melanopsi palestinia II resembles that of Cercaria melanopsi IV described previously from Melanopsis praemorsa snails collected from Yarmouk River, Jordan [15] , except that the number of pairs of the posteriorlateral glands (6 vs 7) are different. It resembles Sanguinicola cercaria which develops in Potamopyrgus antipodarum snails and was recoverd in France [24] .…”

“…Moreover, it belongs to"Pusilla" sub-type due to the possession of two pairs of penetration glands, undeveloped gut, and development within small ovoid sporocyst, except that the number of flame cells is greater (18 vs 12) [19] . Cercaria melanopsi palestinia I is closely related to Cercaria melanopsi I described previously from M. praemorsa snails collected from Yarmouk River, Jordan [15] , except that the number of pairs of penetration glands (2 vs 3) and the number of flame cells (18 vs 20) are different.…”

“…Freshwater gastropods of the genus Melanopsis snails are apparently obligate intermediate hosts for many species of trematode parasites that may exist in several vertebrate hosts [2,4,[7][8][9]13,15,16] . A detailed description of the various types of cercariae has been reported previously [17][18][19][20][21] .…”

Three new species of Xiphidiocercariae from the thiarid snail Thiara tuberculata in Palakkad, Kerala, India

“…Among the known virgulate Xiphidiocercariae with 3 pairs of penetration glands and spinose body, the present cercaria comes close to the description of cercaria of Acanthatrium oregonense by Burns (1961), Cercaria dracodysiana by Hall and Groves (1963), C. etgesi by Nasir (1963) and C. melanopsi III by Ismail and Abdel-Hafez (1983). The present form is distinct from the others in size of body and stylet, shape of virgula organ, arrangement of pentration glands and in the nature of their contents.…”