Full text
| |
| Author(s): |
Matheus Fortes Santos
Total Authors: 1
|
| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB) |
| Defense date: | 2014-12-09 |
| Examining board members: |
Paulo Takeo Sano;
Renato Goldenberg;
Marcos Eduardo Guerra Sobral
|
| Advisor: | Paulo Takeo Sano; Evelyne Jill Lucas |
| Abstract | |
The Neotropical species of Myrtaceae belong to the tribe Myrteae, which is most diverse in this region. While the systematics studies of the group have experienced gradual progress, the biogeographic studies are still scanty. \"Myrcia group\" (=Myrcia s.l.), exclusively Neotropical, is one of the seven groups of Myrteae. This group comprises about 700 species in the three recognized genera - Calyptranthes, Marlierea e Myrcia, but the synonymization of the two former in Myrcia is needed. In a recent phylogenetic study, nine groups were proposed in Myrcia s.l., one of them been the clade 7. The aims of this study are to carry out phylogenetic analysis and to conclude the taxonomic revision and nomenclatural updates of the clade 7, and to study the biogeographic patterns of Myrcia s.l. The phylogenetic study of the clade 7 includes 18 of the 22 species inferred for the group, totalizing 105 samples; the parsimony and bayesian analyses were based in the ITS, ndhF, psbA-trnH, trnL and trnQ markers, and the results were compared with the morphology. The collections of 49 herbaria were checked and 15 field expeditions were carried out for the taxonomic revision and nomenclatural updates. In the biogeographic study, the Neotropical region was divided in eight units; in the phylogenetic analysis of Myrcia s.l., which includes five markers and 182 samples, the Paleomyrtinaea fossil (56 Ma) was placed at the crown node of Myrteae and the lineage divergence times were estimated by the lognormal relaxed clock; the DEC model was used for the biogeographic analysis, in which the dispersal constraints were based in the distance and floristic links between the units. The phylogenetic analysis confirm that the clade 7 is monophyletic; the group was morphologically defined and informally named Sympodiomyrcia, which alludes to the sympodial branching found in the vegetative branches and mainly in the basal branching of the inflorescence. The internal relationships show low resolution. Calyptranthes is the sister group of Sympodiomyrcia and the morphology reinforces this relationship. A morphological characterization and an identification key for the species are provided in the taxonomic revision. The taxonomic treatment includes nomenclatural, morphological, geographical, biological and conservational data about each species. Until now, Sympodiomyrcia contains 21 species, which six are undescribed. Concerning the biogeographic study of Myrcia s.l., the Montane Atlantic Forest appears as the ancestral area of several lineages. In contrast, the initial diversification of Calyptranthes probably occurred in the Caribbean region and then the group expanded to the south. The Guiana Shield and the Lowland Atlantic Forest also appear as the ancestral area of Myrcia s.l. lineages. The main diversification events occurred during the Miocene. It is still necessary to expand the sampling, to increase the number of markers and to carry out morphological and biological studies of Myrcia s.l., what will be essential to improve the knowledge of the phylogenetic and biogeographic histories of this big group (AU) | |
| FAPESP's process: | 10/09473-0 - Revision, phylogeny and biogeography of the clade Myrcia pulchra Group (Myrcia s.l., Myrtaceae) |
| Grantee: | Matheus Fortes Santos |
| Support Opportunities: | Scholarships in Brazil - Doctorate |