Abstract. Adult trematodes of two species of the genus Plagiorchis were found in the southern Far East of Russia: one species in the intestine of a naturally infected Japanese large-footed bat (Myotis macrodactylus) and the other in a golden hamster (Mesocricetus auratus) experimentally infected with metacercariae collected from a stonefly. On the basis of morphological and molecular studies, the trematode individuals found in the bat were identified as Plagiorchis koreanus, which confirms that this species is cosmopolitan. The trematodes reared in the hamster were similar in their morphological features to the European Plagiorchis eutamiatis. However, due to the lack of nucleotide sequences for this species from the type region, the southern Far East of Russia trematodes, found in this study, were provisionally designated as Plagiorchis cf. eutamiatis. In addition, the phylogenetic reconstruction based on a mitochondrial marker revealed inconsistency of the data obtained from cercariae diagnosed as a single species, Plagiorchis elegans. Our data also indicate that the specimens available in the NCBI database referred to as Plagiorchis multiglandularis and Plagiorchis neomidis belong to the same species.
