Systematics Section / ASPT
Nagalingum, Nathalie S. , Pryer, Kathleen M. , Schneider, Harald , Hearn, David .
The age of heterosporous ferns as estimated by molecular divergence dating and the fossil record.
THE estimation of divergence times using molecular phylogenetic data has become commonplace in systematic and evolutionary studies. Although fossils are routinely used as constraints in these analyses, paleontological data is often minimally exploited. Compared to most plants, the fossil record of heterosporous ferns (Salviniales) is profuse and diverse, and therefore, highly informative in understanding the evolution of this group. In this study, we exploit the wealth of fossil data and use molecular approaches to estimate the age of origin of heterosporous ferns, the extant families Marsileaceae and Salviniaceae, and their five constituent genera (Marsilea, Regnellidium, Pilularia, Salvinia, and Azolla). We critically evaluate and compare ages obtained from available fossil evidence, a fossil-based sister lineage approach, and different molecular methods (penalized likelihood, and Bayesian divergence time estimation). We demonstrate that both DNA sequence and paleontological data can result in a clearer picture of historical and evolutionary events.
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1 - Duke University, Department of Biology, 139 Biological Sciences Building, PO Box 90338, Durham, North Carolina, 27708, USA
2 - University of Goettingen, Department of Systematic Botany, Albrecht von Haller Institute for Plant Sciences, Untere Karspuele 2, Goettingen, D-37073, Germany
3 - University of Arizona, Department of Ecology and Evolutionary Biology, P.O. Box 210088, Tucson, Arizona, 85721, USA
molecular divergence time estimates
Presentation Type: Oral Paper:Papers for Sections
Location: 144/Performing Arts Center
Date: Tuesday, August 1st, 2006
Time: 8:30 AM