Resolving the taxonomic identity of commercially cultivated Korean Pyropia dentata (Bangiophyceae, Rhodophyta): genomic, molecular, morphological, and biogeographic evidence for Pyropia eudentata sp. nov.

Pyropia dentata is one of the most economically important seaweed species widely cultivated in East Asia, particularly in Korea, known as ‘Gob-Chang Gim.’ Its taxonomic identity has long been obscured by heavy reliance on morphological characters, leading to frequent misidentification. Recently, a study focusing on Japanese populations identified two clades within the Py. dentata complex; however, they were treated as a single species based on the rbcL sequences. Consequently, further studies are needed to better understand the taxonomy and diversity of the group, particularly with respect to Korean populations. Here, we reassessed the phylogenetic relationships within the Py. dentata complex and evaluated the cryptic diversity of Korean populations by integrating organelle genomes and multilocus phylogenetic analyses with morphological and biogeographic data. Our results show the lineage including Korean populations was clearly distinct from the lineage represented by type-locality-derived material of Py. dentata. Species delimitation analyses also support the recognition of two separate species. This distinction is further supported by comparisons of newly sequenced organelle genomes from the three sibling species, which revealed differences in genome structure, phylogenomic relationships, and genetic distances among coding genes. Based on this integrative genomic evidence and the observed morphological differences, we propose that this lineage represents a new species, described herein as Pyropia eudentata sp. nov. This taxonomic revision carries important implications for future aquaculture, species classification, and the management of biological data in Pyropia.