A prosogonotrematid digenean (Trematoda) obtained from the marine fishMonacanthus monoceros (Day) of Bay of Bengal is referable to the speciesProsogonotrema carangi Velasquez, 1961. But extreme variability in structures like vitelline tubules, intestinal caeca and/or measurements of suckers and body parts have prompted Nasir to propose drastic synonymy reducing all eight hitherto known species to the typeP. bilabiatum. P. carangi however appears to be distinct. The familyProsogonotrematidae is reviewed including the new genusBhaleraoia Srivastava 1948 described fully by Sahai and Srivastava.