American Journal of Botany · 2010 · 822 citations · 86 references
It has been eight years since the last comprehensive analysis of angiosperm divergence times. The study seeks to generate updated divergence‑time estimates for major angiosperm clades using improved relaxed‑clock methods, to clarify their evolutionary history and diversification patterns. The authors applied a relaxed‑clock phylogenetic model with 36 fossil calibrations across 567 taxa to estimate the ages of angiosperms and key lineages. The resulting estimates place the crown age of angiosperms at 167–199 Ma and major clades such as Mesangiospermae, Gunneridae, Rosidae, and Asteridae at 139–156, 109–139, 108–121, and 101–119 Ma, respectively—generally younger than recent molecular studies and closely matching the fossil record.
• Premise of the study : It has been 8 years since the last comprehensive analysis of divergence times across the angiosperms. Given recent methodological improvements in estimating divergence times, refined understanding of relationships among major angiosperm lineages, and the immense interest in using large angiosperm phylogenies to investigate questions in ecology and comparative biology, new estimates of the ages of the major clades are badly needed. Improved estimations of divergence times will concomitantly improve our understanding of both the evolutionary history of the angiosperms and the patterns and processes that have led to this highly diverse clade. • Methods : We simultaneously estimated the age of the angiosperms and the divergence times of key angiosperm lineages, using 36 calibration points for 567 taxa and a “relaxed clock” methodology that does not assume any correlation between rates, thus allowing for lineage‐specific rate heterogeneity. • Key results : Based on the analysis for which we set fossils to fit lognormal priors, we obtained an estimated age of the angiosperms of 167–199 Ma and the following age estimates for major angiosperm clades: Mesangiospermae (139–156 Ma); Gunneridae (109–139 Ma); Rosidae (108–121 Ma); Asteridae (101–119 Ma). • Conclusions : With the exception of the age of the angiosperms themselves, these age estimates are generally younger than other recent molecular estimates and very close to dates inferred from the fossil record. We also provide dates for all major angiosperm clades (including 45 orders and 335 families [208 stem group age only, 127 both stem and crown group ages], sensu APG III). Our analyses provide a new comprehensive source of reference dates for major angiosperm clades that we hope will be of broad utility.
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BEAST: Bayesian evolutionary analysis by sampling trees
Alexei J. Drummond, Andrew Rambaut · BMC Evolutionary Biology · 2007 · 13K citations · Full text
Relaxed Phylogenetics and Dating with Confidence
Alexei J. Drummond, Simon Y. W. Ho, Matthew J. Phillips et al. · PLoS Biology · 2006 · 6.4K citations · Full text