Evolution and Diversification in the Sapindales
Clayton, Joshua W. , Fernando, Edwino S. , Soltis, Pamela S. , Soltis, Douglas E. .
Historical biogeography and diversification in the Tree-of-Heaven family (Simaroubaceae, Sapindales).
Simaroubaceae are a small, yet morphologically diverse family of tropical and temperate trees and shrubs. The family has 21 genera and approx. 100 species, and appears to have a complex history of migration, diversification and extinction. Molecular data from three plastid genes, rbcL, atpB and matK, and a nuclear gene, phyC (approx. 6000 total bp), were used to reconstruct the phylogeny of the family and clarify generic limits, employing Maximum Parsimony and Bayesian approaches. Comparisons among Bayesian analyses, partitioned variously by gene and codon position, reveal that the most complex method of partitioning best explains the data under a Bayes factor criterion. However, tree topology did not change among partitioning strategies, suggesting the phylogenetic signal is robust and resistant to model misspecification. Divergence times were estimated for the phylogeny using BEAST, calibrated with fruit fossils of Ailanthus and Leitneria. The dated phylogeny is used to examine past migration events in relation to climatic and tectonic activity throughout the Tertiary, and infer dispersal and vicariance scenarios. Results add to a growing body of knowledge concerning the importance of the North Atlantic Land Bridge as a migration route for tropical groups, but also suggests long-distance dispersal has played a vital role in shaping current species distributions. Morphological diversity that is comparable to larger angiosperm clades of a similar age, and the broader past distributions of Ailanthus and Leitneria, suggest extinction cannot be overlooked in the evolutionary history of Simaroubaceae.
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1 - University of Florida, Botany, PO Box 117800, Gainesville, FL, 32611, USA
2 - University of the Philippines at Los Banos, Forest Biological Sciences, College, 4301 Laguna, Philippines
3 - Florida Museum of Natural History, Dickinson Hall, P.O. Box 117800, Gainesville, Florida, 32611, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Boulevard B/Hilton
Date: Tuesday, July 10th, 2007
Time: 8:45 AM