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.

Trichodina amblypharyngodoni sp. n. and Trichodina hoffmani Wellborn, 1967 (Ciliophora: Trichodinidae) from the freshwater fishes in the Baikka Beel of Moulvibazar district in Sylhet division, Bangladesh

During a survey on species diversity of trichodinid ciliates from freshwater fishes in the Baikka Beel of Moulvibazar district in Sylhet division from January to December 2015, two species of ciliates were identified, of which one is new to science. Trichodina hoffmani Wellborn, 1967 is collected from the gills of Mystus tengara, and Trichodina amblypharyngodoni sp. n. is described from Amblypharyngodon mola using the silver nitrate impregnation method. T. amblypharyngodoni sp. n. is characterized by having a large, darkly stained central area; rectangularly-rounded butterspoon-shaped blade with very narrow interblade space and blunt tangent point; indistinct anterior and posterior blade apophysis, but a rounded apex near the base of the central part of denticle; slender, sometimes slightly triangular central part with rounded tip; and filamentous, curved, anteriorly directed rays with inflated tip and indistinct central groove. Based on these characters and the unique shape and absence of variability of the denticles among the silver impregnated specimens of the present species, it may be said that to a lesser extent, it resembles Trichodina prowazeki Grupcheva and Lom, 1980.

Trichodina shitalakshyae sp. n. and Trichodina acuta Lom, 1961 (Ciliophora: Trichodinidae) from the freshwater fishes in the Shitalakshya River, Bangladesh.

Two trichodinid species were identified from freshwater fishes, Mystus bleekeri and Glossogobius giuris, in the Shitalakshya River of Gazipur district, Bangladesh. Trichodina acuta Lom, 1961 is found for the first time in Bangladesh. Trichodina shitalakshyae sp. n. is characterized by having an undivided clear central area in the adhesive disc with a rounded or slightly undulated perimeter containing a few dark granules which form patches; elongated and rectangular blade with large interblade space and blunt tangent point; indistinct anterior blade apophysis and a shallow apex at the base of blade that never extends beyond the Y+1 axis; moderately wide and triangular central part with blunt point; and space between tip of ray and central clear area forms a wide impregnated ring. Based on these characters and the unique shape and absence of variability of the denticles among the silver impregnated specimens of the present species, it resembles Trichodina porocephalusi Asmat, 2001.