Diversity, Distribution, and Molecular Systematics of Octocorals (Coelenterata: Anthozoa) of the Penghu Archipelago, Taiwan

The 1st ever surveys of octocorals in the Penghu Archipelago, Taiwan were conducted in 2006 and 2009. Scuba collections were carried out at 17 sites in northern, eastern, south-central, and southern parts of the archipelago. The collection, comprising about 250 specimens, yielded 34 species of the family Alcyoniidae belonging to Aldersladum, Cladiella, Klyxum, Lobophytum, Sarcophyton, and Sinularia. These include 6 new species that were recently described and another 15 records new to Taiwanese reefs. The northern collection sites featured a lower number of species compared to most of the central/southern or southern ones. To facilitate identification of octocoral species in future surveys, DNA sequences were obtained for the mitochondrial barcoding markers, COI and mtMutS, and for Cladiella and Klyxum only, nuclear 28S rDNA. These molecular markers reliably identified specimens to genus and clade, but could not discriminate among species within some clades. Phylogenetic reconstructions based on the barcode markers revealed paraphyly among Cladiella, Klyxum, and Aldersladum, thus emphasizing the need for taxonomic revisions of these genera. These results highlight the importance of octocoral surveys to elucidate patterns of biodiversity and zoogeography in the East and South China Seas, including their marginal reef systems.