Systematics/Phytogeography / Taxonomie/ Section
Lavin, Matt , Paganucci de Queiroz, Luciano , Pennington, Richard , Hughes, Colin E. , Sarkinen, Tiina , Lewis, Gwilym P. , Delgado Salinas, Alfonso .
Ecological and geographical phylogenetic structure in Coursetia (Leguminosae): niche conservation and dispersal limitation may explain the historical biogeography of groups centered in seasonally dry tropical forests.
Phylogenetic analysis of the genus Coursetia reveals many geographically confined monophyletic clades that are mostly restricted to the New World seasonally dry tropical forests. Multiple accessions of narrowly distributed species coalesce, have stem age estimates that average around several million years, and are sister to geographically adjacent species with similar attributes. This pattern is found even with sequences from the nuclear ribosomal ITS/5.8S region, but is corroborated by analysis of chloroplast loci such as the trnL-F spacer and the trnD-T region. Indeed, initial interpretations of paralogy in the ITS/5.8S region turned out to be orthologous sequences that revealed one case of a species that was misclassified due to misinterpreted morphology and three cases of undescribed species. The three undescribed species were previously mentioned in literature has having peculiar morphologies and geographies but not enough to warrant specific status. Multiple accessions of the undescribed species also coalesced, were allopatric relative to sister lineages, and had old age estimates. In sum, the seasonally dry tropical forest could biogeographically constrain the phylogeny of clades that have a predilection for this vegetation type. The long term persistent nature of this vegetation along with its patchy distribution could be dispersal limiting over evolutionary time frames such the ecological and geographical structuring emerges in the constituent lineages.
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1 - Montana State University, Department of Plant Sciences, Bozeman, Montana, 59717, USA
2 - Universidade Estadual de Feira de Santana, Feira de Santana, Brazil
3 - Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh, Scotland, EH3 5LR, United Kingdom
4 - University of Oxford, Department of Plant Sciences, South Parks Road, Oxford, Oxfordshire, OX1 3RB, United Kingdom
5 - University of Oxford, Plant Sciences, Oxfordshire, United Kingdom
6 - Royal Botanic Gardens, Kew, Herbarium, Richmond, Surrey, TW9 3AB, England
7 - Insituto de Biología, U.N.A.M., Botánica, Mexico City, D.F., México
Seasonal Dry Tropical Ecosystems
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 11:15 AM