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

ABSTRACT Traditional morphology-based investigations of the red algal genera Devaleraea and Palmaria (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, psaA, ITS) phylogenetic analyses. Our analyses indicate that diversity was previously underestimated for the Devaleraea/Palmaria complex. We describe three additional species of Devaleraea: D. sakhalinensis sp. nov., D. kussakinii sp. nov. and D. urupiana sp. nov. We consider D. titlyanoviorum 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 D. titlyanoviorum are described here as D. sakhalinensis. We confirmed that the genus Palmaria is not monotypic. It includes at least two species: P. palmata in the North Atlantic and P. moniliformis in the north-western Pacific. We expand the known ranges of D. callophylloides, D. mollis and P. hecatensis in the north-western Pacific southwards and find that D. stenogona is confined to the northern part of the Sea of Japan. The distribution patterns of species of the genera Devaleraea and Palmaria are discussed in relation to the oceanography of the north-western Pacific. HIGHLIGHTS Three new species of the genus Devaleraea are proposed. The genus Palmaria is not monotypic and includes at least two species, P. moniliformis and P. palmata.