Guimaraes, Paulo J. F. , Penneys, Darin S. , Michelangeli, Fabian A. .
A phylogenetic analysis of Neotropical Melastomeae (Melastomataceae), with an emphasis on Tibouchina .
In the last series of family-wide phylogenetic analysis of the Melastomataceae in 2001, Renner and Meyer, and Clausing and Renner redefined the tribe Melastomeae to include 47-48 genera and almost 600 species. The tribe was defined by seed and anther characters, and it constitutes the only group in the subfamily Melastomatoideae that contain species from both the New and Old World. However, many Neotropical taxa were not sampled, thus the relationships among genera of New World Melastomeae have remained problematic. For this study, we sampled 28 genera of New World Melastomeae, with only four monotypic and poorly collected genera missing, as well as representatives of Old World Melastomeae and members of the Microlicieae that were used as outgroups. In total, over 150 species were sequenced for nrITS and the plastid spacers accD-psaI and psbKL. New World Melastomeae are not resolved as monophyletic, as a group of Old World genera (Osbeckia, Melastoma, Tristemma and allied genera) are resolved nested within it. Sister to this Old World clade, we recover a clade that contains the large genus, Tibouchina (with over 250 described species), with at least 13 other Neotropical genera. Moreover, Tibouchina is not recovered as monophyletic because Brachyotum, Heterocentron, Itatiaia, Microlepis, Svitramia, and Tibouchinopsis are nested within it, even though all of these genera are recovered as monophyletic, or nearly so. Many of the previously recognized sections of Tibouchina are recovered as monophyletic or paraphyletic. Pachyloma is recovered in a clade with Rhexia and Arthrostemma, as predicted by Renner and Meyer, but the position of this clade relative to other Neotropical and Old World Melastomeae is still unclear.
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1 - Jardim Botanico do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
2 - California Academy of Sciences, Department of Botany, 55 Music Concourse Drive, Golden Gate Park, San Francisco, CA, 94118, USA
3 - The New York Botanical Garden, Institute of Systematic Botany, 200th St. & Southern Blvd., Bronx, NY, 10458-5126, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 556B/Convention Center
Date: Wednesday, August 4th, 2010
Time: 4:15 PM