Life History of Paramonostomum philippinensis sp. n. (Trematoda: Digenea: Notocotylidae)

Abstract

Thiara riquetti from brackish ponds on Luzon Island shed triocellate monostome cercariae which encysted on opercula of the snails. Ovigerous adults of P. philippinensis were obtained from the intestinal ceca of chicks 12 to 15 days after they were fed metacercariae. Ducklings that died 4 days following experimental infection yielded only immature worms. Stages in the life history are described, and the range of the genus Paramonostomum is extended to the Philippines. From November 1964 to October 1967, 24,550 Thiara riquetti Grateloup, a brackish water snail from fishponds of the Philippine Fisheries Commission, Dagat-dagatan Experimental Station, Malabon, Rizal, Luzon Island, Philippines, were examined for larval trematodes. Among those found was a cercaria similar to Cercaria caribbea I Cable, 1956. Less than 1% of the snails harbored developmental stages of that larva and about 3% had metacercariae on their opercula. Gravid adults identified as Paramonostomum philippinensis sp. n. were recovered 12 to 15 days later, from the intestinal ceca of hatchery-raised chicks fed with metacercariae taken from the opercula of infected snails and the bottom of culture