Systematics/Phytogeography / Taxonomie/ Section
Nagalingum, Nathalie , Mathews, Sarah , Doyle, James A. .
The impact of morphology and fossils in phylogenies: a case study using seed plants.
Fossils provide the only link to past diversity and, particularly in seed plants, they are the only evidence of the sequence of events and intermediate morphologies on the long stem lineages leading to living taxa. They are, therefore, essential for understanding plant evolution. Using a seed plant data set, we present an empirical study exploring the role of morphology and fossils in phylogenetic analyses. Our data set incorporates 14 fossils and 22 living taxa; all taxa are scored for over 130 morphological characters, and most living taxa are represented by whole chloroplast genomes. After comparison of topologies obtained using either morphology or molecules, we conduct analyses based on total evidence and constrained (molecular scaffold) approaches using maximum parsimony and Bayesian inference. We evaluate the effects of missing data, the informativeness of particular suites of characters, and the potential utility of partitioning data sets. Additional data exploration will include experiments to examine whether or by how much the phylogenetic inference of relationships among the major gymnosperm lineages is sensitive to inclusion of the fossil taxa from crown and stem seed plant lineages. Our results demonstrate the importance of morphology and fossils in inferring phylogenies.
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1 - Harvard University, Arnold Arboretum, 22 Divinity Ave, Harvard University Herbaria, Cambridge, MA, 02138, USA
2 - Harvard University, Arnold Arboretum, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, Massachusetts, 02138, USA
3 - University of California, Davis, Section of Evolution and Ecology, One Shields Ave., Davis, California, 95616, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Room 6/Woodward
Date: Tuesday, July 29th, 2008
Time: 8:30 AM