Bostrychia edisondepaulae (Rhodophyta, Rhodomelaceae), a new freshwater species from Brazil

Resumo

Samples tentatively identified as Bostrychia moritziana were collected in freshwater habitats from two locations in the States of São Paulo (Cananéia) and Rio de Janeiro (Trindade), southeastern Brazil. Culture observations for more than 20 years, combined with analyses of DNA sequences of the mitochondrial (COI-5P) and the plastid (rbcL) genes, supported the proposal of a new species of Bostrychia. The new species is morphologically closely related to B. moritziana and B. radicans, but it is phylogenetically distinguished by DNA sequence data. Reproduction in culture was by abortive tetrasporangia. Phylogenetic analyses showed that the Brazilian samples formed a clade that was sister to B. moritziana sequences in the rbcL tree. Likewise, in the COI tree, these samples were a clade but nested among three B. moritziana sequences. The morphological similarity of the new species with B. moritziana and B. radicans, which have been regarded as species complexes, is intriguing. The sequence divergences found in this study (> 6% for rbcL and COI-5P) suggested that the new species is distant enough to be recognized as a distinct species in comparison to the closest species B. moritziana.