The first record of two trichodinid ectoparasites, Trichodina pseudoheterodentata Tang et al. 2017 and Trichodina hafizuddini Asmat, 2005 (Ciliophora: Peritricha) from the freshwater fishes in the Baikka Beel of Moulvibazar district in Sylhet division, Bangladesh

A parasitological investigation on trichodinid ciliates from several freshwater fishes in the Baikka Beel of Moulvibazar district of Sylhet was carried out between January and December 2015. During the investigation period, two parasitic trichodinid ciliates (Ciliophora: Peritrichia), Trichodina pseudoheterodentata Tang et al. 2017 and Trichodina hafizuddini Asmat, 2005 were morphologically studied and described with using the silver nitrate impregnation technique. Trichodina pseudoheterodentata was isolated from the gills of Mystus bleekeri, while Trichodina hafizuddini from the gills of Amblypharyngodon mola. This investigation has been revealed that these two Trichodina species fall within the range of morphometry and agree closely in the overall appearance of the adhesive disc with the original populations. Geographical variation was also observed by considering the body size and number of the denticles. Depending on country’s available taxonomical survey on trichodinid ciliates, this study is the first formal report on these trichodinids from any part of Bangladesh.