Morphological and molecular investigations shed light on diversity and distribution of Palmariaceae in the north-western Pacific

Traditional morphology-based investigations of the red algal genera <i>Devaleraea</i> and <i>Palmaria</i> (Palmariaceae, Rhodophyta) fail to provide accurate accounts of diversity and distribution for species from the Russian coast of the north-western Pacific. Consequently, there is much disagreement and taxonomic uncertainty regarding several species. To resolve these issues we conducted a molecular-assisted investigation that included a DNA barcode survey (COI-5’) and multilocus (COI-5’, cob, <i>psa</i>A, ITS) phylogenetic analyses. Our analyses indicate that diversity was previously underestimated for the <i>Devaleraea</i>/<i>Palmaria</i> complex. We describe three additional species of <i>Devaleraea: D. sakhalinensis</i> sp. nov., <i>D. kussakinii</i> sp. nov. and <i>D. urupiana</i> sp. nov. We consider <i>D. titlyanoviorum</i> to be an alga with abundant proliferations from the margins, branching to several orders, that is known only from Kunashir Island. Algae from Sakhalin Island and the mainland coast of the Sea of Japan previously identified as <i>D. titlyanoviorum</i> are described here as <i>D. sakhalinensis</i>. We confirmed that the genus <i>Palmaria</i> is not monotypic. It includes at least two species: <i>P. palmata</i> in the North Atlantic and <i>P. moniliformis</i> in the north-western Pacific. We expand the known ranges of <i>D. callophylloides, D. mollis</i> and <i>P. hecatensis</i> in the north-western Pacific southwards and find that <i>D. stenogona</i> is confined to the northern part of the Sea of Japan. The distribution patterns of species of the genera <i>Devaleraea</i> and <i>Palmaria</i> are discussed in relation to the oceanography of the north-western Pacific. Three new species of the genus <i>Devaleraea</i> are proposed.The genus <i>Palmaria</i> is not monotypic and includes at least two species, <i>P. moniliformis</i> and <i>P. palmata.</i> Three new species of the genus <i>Devaleraea</i> are proposed. The genus <i>Palmaria</i> is not monotypic and includes at least two species, <i>P. moniliformis</i> and <i>P. palmata.</i>