Abstract
Specimens of the genus Orobdella Oka, 1895 from Gageodo Island, Korea, are identified as Orobdella tsushimensis Nakano, 2011 based on the following characteristics: IV uniannulate; 1/2+5 annuli between the gonopores; a bottle-shaped gastroporal duct; and epididymides in XVII-XIX. The diagnosis of O. tsushimensis is amended since the Korean specimens have a reddish dorsal surface and ovate atrial cornua. Phylogenetic analyses using mitochondrial COI, tRNA^<Cys>, tRNA^<Met>, 12S rRNA, tRNA^<Val>, and 16S rRNA markers show that the specimen from Gageodo Island and those identified as O. tsushimensis from Tsushima Island, Japan, form a monophyletic clade, confirming the species identification of the former. This is the first record of the genus Orobdella, and of the monotypic family Orobdellidae, from Korea.
