Wahlert, Gregory A. , Ballard, H. E. .
Phylogeny, biogeography, and a taxonomic revision of Rinorea (Violaceae) from Madagascar and the Comoro Islands.
Rinorea is a pantropical genus of shrubs and small trees and is the second most species-rich genus in the Violaceae with an estimated 225–275 species. The species in Madagascar and the Comoro Islands have not been revised since 1949, nor has there been an adequate understanding of infrageneric groupings, phylogeny, and biogeography for the genus. There were four goals in this study: 1) a taxonomic revision of Rinorea in Madagascar and the Comoro Islands, 2) a revised infrageneric classification of the African and Malagasy species, 3) phylogenetic reconstruction of the “core” Rinorea inferred from chloroplast DNA sequences, and 4) inferences of biogeographic history of the Malagasy species. Results from the taxonomic revision recognizes ca. 45 species, including 12 new species. The newly proposed infrageneric classification of African and Malagasy Rinorea—based on morphometric and molecular phylogenetic evidence—recognizes 11 taxonomic sections, including four new sections. Phylogenetic analyses of the of three chloroplast regions (trnL-trnF spacer, trnL intron, and trnD-trnE spacer) provided strong branch support for a “core” group of Rinorea interior to the divergent R. apiculata group and sister to the rest of the Violaceae. Biogeographic analyses suggest at least four dispersals from Africa to Madagascar, whereas the endemic R. subsection Verticillatae shows a sister relationship to the Asian species. These new taxonomic and phylogenetic results for Malagasy Rinorea show a rate of endemism in excess of 90%. Phylogenetic and biogeographic analyses reveal that ca. 37% of species have phylogenetic affinities to African species and the remaining 63% are more closely related to Asian species. Several species are critically endangered or presumed extinct, while others are represented by substantial populations in protected areas.
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1 - Ohio University, Department of Environmental & Plant Biology, Porter Hall, Richland Avenue, Athens, Ohio, 45701-2979, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Ballroom B/Convention Center
Date: Monday, August 2nd, 2010
Time: 1:45 PM