A new species of the genus Opisa Boeck, 1876 (Crustacea, Amphipoda, Opisidae) and a new record for Opisa takafuminakanoi from the East Sea, South Korea

Two species of the opisid genus Opisa have been collected from the East Sea of South Korea, one of them described as Opisa parvimana sp. nov.. The new species, O. parvimana sp. nov. is similar to O. odontochela; however, it can be clearly distinguished from this species because it has 12 blunt robust setae in the palm of gnathopod 1. The other collected species, Opisa takafuminakanoi Narahara-Nakano, Kakui & Tomikawa, 2016 is previously known from Japanese waters (southeast of Akkeshi Bay, Hokkaido). Both species are illustrated and compared to related species. A key to Opisa species is also provided.