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Phylogenomics and biogeography of Bocageeae (Annonaceae), amphi-Atlantic and Atlantic-Amazonian tribe

Grant number: 18/11272-5
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): February 01, 2019
Effective date (End): January 31, 2021
Field of knowledge:Biological Sciences - Botany
Principal Investigator:Renato de Mello-Silva
Grantee:Jenifer de Carvalho Lopes Dantas
Home Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Events of vicariance and dispersion are models traditionally applied for explanating biogeographic hypotheses. Primary hypotheses about the disjunctions between South America and Africa and between the Atlantic Forest and the Amazon Forest are based on the Gondwana split during the Cretaceous and the latter on the climatic changes from the Miocene. These events would have forged not only the genesis and distribution of our biomes, but also their composition, affecting together the groups of organisms that compose them. Distributions that do not fit vicariant hypotheses would be explained by ad hoc dispersion and / or extinction hypotheses, such as the gradual dispersion of the Eocene Boreal-tropical corridor. The Atlantic Forest and the Amazon Forest probably formed a continuous forest in South America before the climatic changes of the Miocene had led to its disjunction by the establishment of the "dry diagonal" with expansion of the Cerrado and the Caatinga. Advances achieved in the last decades have tested the relative role of events and hypotheses such as continental drift, the model of forest refuges, the existence of Pleistocene or Tertiary dry arc and the "Atlantis Forest" in biogeographic patterns. Dated phylogenies have shed light on the periods of divergence of lineages, elucidating moments where scenarios of vicariance or dispersion would be favored as processes causing the disjunction of Neotropical forest groups. One of these groups, the Bocageeae tribe of Annonaceae, with seven genera, is compound by Miklua, restricted to Africa, and the others, Cymbopetalum, Porcelia and Trigynaea, occurring in the two Brazilian forest areas, Amazonian and Atlantic Forests, Cardiopetalum, occurring in the Amazon and Cerrado, and Bocagea and Hornschuchia, restricted to the Atlantic Forest. In order to associate the Bocageeae disjunction patterns to the biogeographic events occurring in Gondwana and / or South America, phylogenies of the group with reliable dates of the branches are necessary. Bocageeae is a good model to investigate the biogeographic history of South America because, besides its distribution in the Atlantic Forest and Amazon, it is the only group of Annonaceae with genera endemic to the Atlantic Forest, also distributed in a way to test the biogeographic hypotheses of this biome as refuges, and the "Atlantis Forest". In addition, they are important components of the Amazonian and Atlantic Forest flora, with species still poorly known and defined. This project aims to reconstruct the phylogeny of the Bocageeae tribe using a wide molecular sampling by next generation sequencing, to infer reliable dates for the nodes of this phylogeny and to understand the biogeographic patterns of the Bocageeae tribe with current methods, associating them to the processes of formation of the Atlantic Forest and of the Amazonian Forest, and to produce an updated taxonomic treatment of the tribe, necessary for the conclusion of the works of the Flora of Brazil 2020.