Taxonomic Revision of Cirrodrilus makinoi (Annelida: Clitellata: Branchiobdellida) with a Redescription of C. homodontus

Cirrodrilus makinoi (Yamaguchi, 1934) has not been identified since it was originally described from the Japanese crayfish, Cambaroides japonicus (De Haan, 1841) on Hokkaido Island, northern Japan. A critical morphological comparison of the original and new material of C. makinoi with those of closely related C. tsugarensis Gelder and Ohtaka, 2000, from Honshu Island, reveals there are no differentiating morphological character to separate the two species. A molecular study using the mitochondrial cytochrome c oxidase subunit I gene supports this view, therefore, C. tsugarensis becomes a subjective junior synonym of C. makinoi. Another species resembling C. makinoi, C. homodontus Yamaguchi, 1932 is confirmed to be a distinct species and both are redescribed based on the original and new material.