A DNA barcode library for crustose brown algal species

The crustose brown algae are particularly difficult to identify even for experienced taxonomists due to their simple morphology and reduced number of diagnostic characters. In order to facilitate the process of identification and improve its accuracy, we have initiated a DNA barcode (cytochrome oxidase 1, COI-5P) reference library for these species. Analyses of COI-5P data collected to date from 120 specimens have yielded 29 genetic groups of which 19 are likely assignable to the Ralfsiales. Among these, 24 samples collected as Ralfsia fungiformis resolved as three species groups, while 54 samples of Ralfsia verrucosa resolved as 10 species groups, which suggests extensive overlooked diversity within this widespread but often overlooked genus. Of the 19 Ralfsialean genetic groups uncovered here, six are represented by fewer than three collections and we continue to uncover new genetic groups as we expand our sampling, at both local (e.g., habitat exploration) and global scales. Our preliminary results strongly indicate that the species-level diversity of brown algal crusts is clearly underappreciated.