DNA barcoding reveals high diversity in the Gelidiales of the Brazilian southeast coast

Abstract

Abstract Morphological identification of species in the order Gelidiales can be difficult and controversial because of phenotypic plasticity, the low numbers of reproductive specimens and poorly defined taxonomic boundaries. A DNA barcoding survey of Brazilian specimens of Gelidiales, employing neighbor-joining and Automatic Barcode Gap Discovery analyses, indicated the presence of 23 statistically robust primary species hypotheses (PSH). In addition to the cytochrome oxidase I gene (COI-5P), the chloroplast universal plastid amplicon (UPA) marker was also sequenced and submitted to the same analyses. Representatives of each COI-5P/UPA PSH were selected for rbc L sequence analysis to further corroborate the occurrence of 23 species and to infer their phylogenetic relationships. These analyses confirmed the identity of six species previously cited for Brazil: Gelidiella acerosa , G . ligulata , Gelidium crinale , G . floridanum , Pterocladiella bartlettii and P . capillacea . Three new reports for Brazil were also detected: Gelidium microdonticum , Pterocladiella beachiae and P . australafricanensis . Fourteen species remain unidentified and require detailed morphological evaluation.