Sunflower family in space and time: taxonomy, phylogenomics, historical biogeography and macroevolution of Barnadesioideae

• Ano de defesa: 2019
• Autor(a) principal: Ferreira, Paola de Lima
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Barnadesieae; Biogeografia; Biogeography; Compositae; Filogenia; Macroevolução; Macroevolution; Phylogeny; Taxonomia; Taxonomy
• Link de acesso: http://www.teses.usp.br/teses/disponiveis/59/59139/tde-10122019-143659/

The subfamily Barnadesioideae (Compositae) comprises ten genera and 84 species endemics to South America, distributed from Venezuela to Argentina, being mainly found in xeromorphic areas along the Andes and Patagonia. The interest in Barnadesioideae has considerably increased since they were recovered as sister to the rest of Compositae. Robust phylogenetic hypotheses allied to biogeographic, morphological and macroevolutionary studies can provide insights into the origin and diversification of the family as a whole. Previous phylogenetic studies based on morphological, molecular or combined datasets have been proposed for Barnadesioideae in the last 20 years, but their results were incongruent and did not have extensive molecular markers or taxonomic sampling. On the other hand, biogeographic hypothesis for the group has never been proposed using the fossils described for the group as calibration points and macroevolutionary studies have never been investigated. In this work, we proposed a phylogenetic hypothesis based on Next- Generation sequencing data that includes nearly 1,000 nuclear markers and almost complete plastid genomes for all those species. Our phylogenetic hypothesis comprises 9 of the 10 genera and about 60% of the species, and resolves the relationships with high support in the branches, clarifying their contentious clades, although the relationships in the Chuquiraga, Doniophyton and Duseniella clade remain unresolved due to low support in the branches. The phylogenetic tree inferred here was the first study to infer the divergence times using the fossils described for the subfamily as a calibration method. The biogeographic reconstruction proposes that Barnadesioideae originated in the Eocene at 49 million years ago, and the diversification of the most recent common ancestor of the genera would have started about 20 million years ago during the Miocene. Diversification studies propose that extinction and speciation rates were homogeneous and constant though time, and any shift was detected in the phylogeny. In addition to systematics, biogeographic and macroevolutionary studies, a generic synopsis for Barnadesioideae was also performed, updating the genera circumscription in the light of the new nomenclatural changes developed during the years studying the subfamily. The synopsis includes a key, updated and expanded morphological descriptions, geographical distribution maps, photographs of all genera as well as the morphological diversity of the apical and basal anther appendages. Together with the objectives and main results presented here, important collaborations were established resulting in a review and description of chemical compounds that were already published and certainly contribute to the evolutionary insights into the group and support its delimitation.