RESEARCH ARTICLE Diversity in a Cold Hot-Spot: DNA-Barcoding Reveals Patterns of Evolution among Antarctic Demosponges (Class Demospongiae, Phylum Porifera)

Background The approximately 350 demosponge species that have been described from Antarctica rep-resent a faunistic component distinct from that of neighboring regions. Sponges provide structure to the Antarctic benthos and refuge to other invertebrates, and can be dominant in some communities. Despite the importance of sponges in the Antarctic subtidal environ-ment, sponge DNA barcodes are scarce but can provide insight into the evolutionary rela-tionships of this unique biogeographic province. Methodology/Principal Findings We sequenced the standard barcoding COI region for a comprehensive selection of sponges collected during expeditions to the Ross Sea region in 2004 and 2008, and pro-duced DNA-barcodes for 53 demosponge species covering about 60 % of the species col-lected. The Antarctic sponge communities are phylogenetically diverse, matching the diversity of well-sampled sponge communities in the Lusitanic and Mediterranean marine provinces in the Temperate Northern Atlantic for which molecular data are readily available