Two Plenosominoides Metacercariae from Mountain Crabs in Central and Eastern Thailand

ABSTRACT

Mountain or waterfall crabs from Nakhon Nayok, Saraburi, Kanchanaburi, and Chantaburiprovinces, were collected and examined for trematode metacercariae. Among the metacercariaerecovered, two species of the family Microphallidae were found−Plenosominoides yangshanensis andP. vajrasthirae n comb. The cysts were oval with a thick wall; the metacercariae inside the cyst wallwere fully developed−all organs were visible, but no eggs. Their common features were as followsvitellaria formed into two groups anterior-lateral to each caecum, cirrus pouch incompletely circular,not enclosing a ventral sucker. Little information was known of these trematodes and there has beenno report of their public-health importance.