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Abstract Detail

The Critical Role of Plant Fossils in Divergence Dating Studies

Sauquet, Herve [1], von Balthazar, Maria [2], Carrive, Laetitia [1], Epicoco, Cyril [1], Haevermans, Thomas [3], Jabbour, Florian [4], Massoni, Julien [1], Nadot, Sophie [1], Prieu, Charlotte [1], Simonnet, Franck [1], Tschan, Georg [5], Schoenenberger, Juerg [6].

eFLOWER: A framework for understanding the evolution and diversification of extant and fossil flowers.

Understanding the global patterns of floral evolution in angiosperms has been limited so far by the availability of a morphological data set representing all lineages. Using a new flexible and innovative approach, centered around a multi-user database (PROTEUS), we are building this data set. Unlike most other studies of character evolution at the scale of angiosperms so far, we are only recording exemplar species, allowing explicit reconstructions without assumptions on ancestral states or monophyly of supraspecific taxa and, most importantly, direct matching with the species sampled in molecular phylogenetic trees, offering the possibility of taking branch lengths into account. Here we demonstrate the approach with a pilot study based on the 265-taxon, fossil-calibrated timetree published by Magallon and Castillo in 2009. Using a data set of floral traits of the species sampled in this tree, we reconstruct ancestral states with parsimony as well as several maximum likelihood models of character evolution. In spite of the sparse sampling of angiosperm diversity in this tree, our inferences for key nodes of the phylogeny (angiosperms, mesangiosperms, magnoliids, monocots, eudicots, and core eudicots) show that: 1) the approach is very powerful and worth pursuing with many more species; 2) the gigantic data set that will eventually provide the answers can realistically be built by multiple researchers in a relatively short time; and 3) the results obtained are likely to challenge current hypotheses on large-scale floral evolution, even in parts of the phylogeny most thoroughly investigated so far such as the basal nodes of angiosperms. We then demonstrate how the approach and data set will soon allow to rigorously test the phylogenetic relationships of fossil flowers in a wide context, without assumptions on the larger clade in which they belong. Two fossil taxa, presumably related to the magnoliids and the Ericales, are analyzed in this framework using a molecular backbone approach. Although such analyses can never provide definitive answers, we hope that they soon become commonplace for asserting fossil relationships before using them as age constraints (calibrations) in molecular dating analyses, instead of the widespread use of apomorphy-based and more intuitive approaches. Importantly, all data from the eFLOWER project will be made public upon publication, providing a tool and data set for the community to significantly improve the practice of fossil calibration in divergence dating studies.

Broader Impacts:

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Related Links:
eFLOWER project website

1 - Universite Paris-Sud 11, Lab. Ecologie, Systematique, Evolution (ESE), CNRS UMR 8079, Bat. 360, Orsay, N/A, 91405, France
2 - University of Vienna, Department of Systematic And Evolutionary Botany, Rennweg 14, Vienna, N/A, A-1030, Austria
3 - Museum National díHistoire Naturelle, UMR CNRS 7205, 16 rue Buffon, Paris, 75005, France
4 - National Museum of Natural History, Institute of Systematic Botany And Mycology, 57 Rue Cuvier, CP 39 - Cedex 05, Paris, N/A, 75231, France
5 - University of Gothenburg, Department of Plant and Environmental Sciences, Carl Skottsbergs gata 22B, Goteborg, 413 19, Sweden
6 - University of Vienna, Rennweg 14, Vienna, N/A, AT-1030, Austria

floral evolution
fossil flowers.

Presentation Type: Symposium or Colloquium Presentation
Session: C5
Location: Belle-Chasse/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 10:00 AM
Number: C5003
Abstract ID:206
Candidate for Awards:None

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