Geographic Distribution of Some Species of Trichodinids (Ciliata:Peritricha) Parasitic on Fishes

Abstract

North American Trichodina from Carassius auratus, Lepomis cyanellus, L. macrochirus, Micropterus salmoides, and Rhinichthys atratulus have been studied by the silver-impregnation method and compared with European species. T. reticulata Hirschmann and Partsch, 1955, and T. (Foliella) subtilis Lorn, 1959, originally described from European goldfish, are herein recorded from North America also. T. fultoni Davis, 1947, from Lepomis cyanellus, Micropterus salmoides, and Rhinichthys atratulus is redescribed, and T. domerguei f. magna Lorn, 1961, described from European tench and gudgeon, is considered a synonym. A Trichodina sp. from the gills of Lepomis macrochirus is described; it is almost identical with T. nigra Lom, 1961 from European Rutilus, T. discoidea from centrarchids, and T. tumefaciens from Cottus of North America. Other North American trichodinids are reviewed briefly. Up to the present time, more than 90 species of Trichodina have been described from the gills and skin of marine and freshwater fishes. Many of them have been considered as new only because they were found in a different host and remote geographic area. The descriptions in many cases were inadequate since the uniform body structure of these ciliates yields few characters for solid differentiation of species. However, the recently employed Klein's silver-impregnation technique (Lorn, 1958; Raabe, 1959) clearly reveals details of the adhesive disc which are important features of urceolariid taxonomy. This, together with careful biometrical and other morphological information, represents a good base for taxonomic studies of this group. It is beyond the scope of this communication to present all the problems of trichodinid taxonomy; they can be found in Uzmann and Stickney (1954), Raabe (1959), and Lorn (1958, 1961, 1962). Though insufficient description of some species does not permit us to identify them again, reexamination of a number of species which have been accurately characterized by older methods is possible. This is a study on the geographic distribution of some fish trichodinids, based on a comparison of four species Received for publication 9 April 1963. 30 from some North American fishes from Pennsylvania and West Virginia with material from Cz choslovakia. Trichodina reticulata Hirschmann and