Diversity and phylogeny of red algae (Rhodophyta) of economic and ecological importance

Abstract

The project proposes the survey of the diversity and phylogeny of groups of economic and ecological importance of marine red macroalgae (Rhodophyta), but in which taxonomic issues still persist. The groups addressed are the Corallinophycidae, Halymeniales, Gracilariales and gender Hypnea (Gigartinales), including species with economic potential (e.g. production of hydrocolloids), but with recurring problems for species identification, such as phenotypic plasticity, morphological convergence, need of reproductive structures to identify, among others. Therefore, those are groups in which the use of molecular markers has proven vital to understanding the diversity of species, geographical distribution and phylogenetic affinities. DNA barcodes will be used to analyze hundreds of samples collected extensively on the coast of Brazil and, in some cases, samples from abroad, to better understand the species diversity, distribution and their biogeographic affinities. With this initial screening, the number of species and their geographical distribution will be accessed, followed by morphological analysis and selection of representatives (covering their extremes of geographical distribution) for more detailed studies of phylogeny. Morphological analysis will benefit using this approach, since usually a part of the samples (often the majority) is non-fertile, which makes their identification, in many cases, impossible. With the clusters indicating which samples belong to the same taxon, it is possible to collect and analyze samples at different stages of the life cycle, fertile or not, often growing under broad environmental conditions, which allows a much more complete understanding of the morphology and its variation. (AU)