DNA barcoding reveals cryptic diversity of economic red algae, Pyropia (Bangiales, Rhodophyta): description of novel species from Korea

Red algal genus Pyropia that includes several commercially important species is distributed in wide regions of the world from cold temperate to tropical marine environments. Despite their practical utility, species of this genus are difficult to identify using solely morphological features because they lack reliable diagnostic characteristics. DNA barcoding using mitochondrial COI-5P marker is now well established for red algae. We explored the species diversity of the genus Pyropia in Korea based on the molecular analyses and morphological observations, and confirmed seven species including two new ones, Py. kuniedae, Py. retorta, Py. seriata, Py. tenera, Py. yezoensis, Pyropia submarina sp. nov., and Pyropia vittata sp. nov. In the DNA barcode analysis, Korean Pyropia species were clearly distinguished from other Pyropia species by 2.6 to 17.1% sequence divergences. We also uncovered cryptic species diversity in areas that are remote or not easily approachable such as Ulleung Island in the middle of east sea far from mainland or underwater habitat deeper than 10 m of Udo, Jeju. This study is verifying the probability of more biodiversity from pristine environments and providing the information that DNA barcoding is an efficient way to identify species of Pyropia, the bladed genus of the order Bangiales in Korea.