One specimen of cestode was collected from 32 species of fishes from Maesa Stream, Chiang Mai, Thailand between 1-31 January, 1997.

Only Mystacoleucus marginatus fish was found to be infected which is Ptychobothrium discusae n. sp. differs from the earlier know species in the shape of scolex heart, bothridia oval with having disc, neck absent, number of segments 158-170 in number, testes 190-220 in number, post-ovarian, vas-differens coiled, gravid segments broader than long, ovary finger-like in the last gravid segment.

Uterus square and conical, filled with two types of eggs, uterine pore rounded, near to the anterior margin of the segment and follicular vitellaria.