First record of a potentially introduced leech, Helobdella aff. robusta Shankland, Bissen & Weisblat, 1992 (Hirudinea, Glossiphoniidae), in Japan

Helobdella aff. robusta Shankland, Bissen & Weisblat, 1992 is recorded for the first time from Japan. The haplotype of the cytochrome c oxidase subunit I (COI) gene sequence of a specimen from Japan is identical to that of one collected in California, USA. The dorsal pigmentation pattern of the Japanese specimens is different from that of H. robusta inhabiting North America, but nonetheless, most of their morphological characteristics are con-sistent with the diagnostic features of this species. This species is considered to be of New World origin, and the Japanese population was likely established from a recent introduction