Abstract

The morphology of three ectoparasitic ciliates, Trichodina paraheterodentata sp. nov., Trichodina pseudominuta sp. nov. and Trichodina jialingensis sp. nov., parasitising the freshwater fishes from Chongqing, China, were investigated following dry silver nitrate and the methyl green-pyronin stain. T. paraheterodentatawas found on the skin of Siniperca chuatsi, and is distinguished mainly by the acute triangle-like blade, the well-developed central part, a little curved and robust ray. T. pseudominuta was isolated from the gills of Carassius auratus, and is characterized by the slanting parallelogram, relatively developed central part, long and slim ray arranged in helical form with the tip of ray extending past the Y+1 axis in the whole view of the parasite. T. jialingensis was collected from the gills ofCtenopharyngodon idellus, and is displaying irregular rectangular blade, undeveloped central part and the straight ray. Morphometric data and comparative descriptions of these trichodinids are provided along with details of their prevalence.

Key words: Trichodina, new species, freshwater fish, Siniperca chuatsi, Carassius auratus, Ctenopharyngodon idellus, China.