A new species of Melanochlamys is described based on specimens collected in Russia and Korea. This new species is genetically and anatomically different from other North Pacific species. Phylogenetic analyses of two mitochondrial (COI, 16S) and a nuclear (H3) gene confirmed the results of previous analyses and recovered a clade including specimens of the new species. Although this clade is poorly supported, species delimitation analyses and anatomical differences confirmed it constitutes a distinct species. These results confirm the presence of two distinct species of Melanochlamys in Russia and Korea, bringing the total diversity of the genus in the North Pacific to five.