2020 年 25 巻 1 号 p. 61-73
Four species of alien parasites, Dactylogyrus skrjabini Achmerow, 1954, D. hypophthalmichthys Achmerow, 1952, D. wuhuensis Lee, 1960 (Platyhelminthes: Monogenea: Dactylogyridae), and Sinergasilus lieni Yin, 1949 (Crustacea: Copepoda: Ergasilidae), were collected from the gills of the alien cyprinid, the silver carp Hypophthalmichthys molitrix (Valenciennes, 1844) in the Watarase River flowing into the Watarase Retarding Basin, Tochigi Prefecture, central Japan. These alien parasites represent new geographical records from Japan. The generic position of D. skrjabini has been doubted because its dorsal anchor shape is similar to those of Pellucidhaptor spp. (Dactylogyridae), but the species should be assigned to Dactylogyrus based on the phylogenetic analysis of 28S rDNA made in this study. The scientific name “Pseudergasilus polycolpus Markewitsch, 1939” is an incorrect subsequent spelling of P. undulatus Markewitsch, 1940, and S. lieni is the oldest available name that can be applied to the ergasilid found in this study.
