The chetotaxy of the cercaria of Opisthioglyphe locellus Kossack 1910 (Trematoda, Plagiorchiidae).

The distribution of the tegumentary papillae (chetotaxy) was studied for the cercaria of Opisthioglyphe locellus. The cercariae, which emerge from the freshwater snail Planorbarius corneus L., were treated according to the method of Ginecinskaja and Dobrovol'skij (1963). The papillae were demonstrated after the nomenclature of Richard (1971). The results were identical for cercariae from naturally infected Planorbarius corneus from a pond near Ulm (Germany) and experimentally infected, laboratory-reared snails of the same species. The papillae were distributed symmetrically with few individual variations. The association of the trematode with the subfamily Opisthioglyphinae is corroborated by the chetotaxy of the cercaria. This method also allows the distinction of the cercaria from the most related species. The fact that the excretory system of the cercaria of Opisthioglyphe locellus shows common characteristics with other cercariae of the Opisthioglyphinae (Bock 1982), just like the chetotaxy, emphasizes the taxonomic importance of both criteria.