A new species of Leodice from Korean waters (Annelida, Polychaeta, Eunicidae).

A new eunicid species, Leodice duplexa sp. n. , from intertidal and subtidal habitats in the eastern coast of South Korea is described. The new species is assigned to the C-2 group, and is similar to Leodice antennata , the type species of the genus, in having the following combination of characteristics: moniliform antennae and palps, bidentate compound falcigers, articulated peristomial and notopodial cirri, pectinate branchiae showing bimodal distribution of branchial filaments, and yellow aciculae. However, L. duplexa sp. n. is readily distinguished from L. antennata by the following features: the aciculae are 2-4 in number, with blunt or pointed tips and hammer-headed or bifid tips, and the subacicular hooks are paired in some chaetigers. A detailed description and illustrations are provided for the new species. The validity of the new species is also supported by a genetic comparison using sequences of the mitochondrial cytochrome c oxidase subunit I (COI). A revised key to known Leodice species is provided with a comparison of their morphological characteristics.