Genetic diversity of polychaete annelids from the Saint Peter and Saint Paul Archipelago, Equatorial Atlantic, with description of a new species

The Saint Peter and Saint Paul Archipelago (SPSPA) is located in the mid-equatorial Atlantic and represents a potentially important area for biodiversity research; however, its species diversity remains poorly characterized. Particularly, neglected groups such as invertebrates have not been thoroughly registered or described. For instance, no species inventory is provided for Annelida, the phylum to which segmented worms belong. This study represents the first polychaete species inventory from SPSPA, including genetic and morphological data. We have generated COI mtDNA and 16S rDNA sequences intended as DNA barcode to molecularly identify polychaete species via different methods. First, we used the Barcode of Life Database (BOLD) identification tool; second, we calculated genetic distances and performed maximum likelihood trees with selected sequences from the Genbank database. We found that most species identified from SPSPA are strictly distributed in the Atlantic Ocean. Our methods proved that the accuracy of molecular identification was limited by the shortage of the annelid data available in BOLD and Genbank. Additionally, we describe a new species named Syllis belmontensis sp. nov. Overall, these results can be important resources for comparative studies on the distribution and genetic diversity of polychaetes worldwide.