Constraints on the timescale of animal evolutionary history

Abstract

Dating the tree of life is a core endeavor in evolutionary biology. Rates of evolution are fundamental to nearly every evolutionary model and process. Rates need dates. There is much debate on the most appropriate and reasonable ways in which to date the tree of life, and recent work has highlighted some confusions and complexities that can be avoided. Whether phylogenetic trees are dated after they have been established, or as part of the process of tree finding, practitioners need to know which calibrations to use. We emphasize the importance of identifying crown (not stem) fossils, levels of confidence in their attribution to the crown, current chronostratigraphic precision, the primacy of the host geological formation and asymmetric confidence intervals. Here we present calibrations for 88 key nodes across the phylogeny of animals, ranging from the root of Metazoa to the last common ancestor of Homo sapiens. Close attention to detail is constantly required: for example, the classic bird-mammal date (base of crown Amniota) has often been given as 310-315 Ma; the 2014 international time scale indicates a minimum age of 318 Ma. Michael J. Benton. School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, U.K. mike.benton@bristol.ac.uk Philip C.J. Donoghue. School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, U.K. phil.donoghue@bristol.ac.uk Robert J. Asher, Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, U.K. r.asher@zoo.cam.ac.uk Matt Friedman, Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, U.K. mattf@earth.ox.ac.uk Thomas J. Near, Department of Ecology and Evolutionary Biology, Yale University, P. O. Box 208106, 165 Prospect Street, New Haven, CT 06520-8106, U.S.A. thomas.near@yale.edu Jakob Vinther. School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, U.K. jakob.vinther@bristol.ac.uk PE Article Number: 18.1.1FC Copyright: Society for Vertebrate Paleontology February 2015 Submission: 1 August 2013. Acceptance: 7 December 2014 Benton, Michael J., Donoghue, Philip C.J., Asher, Robert J., Friedman, Matt, Near, Thomas J., and Vinther, Jakob. 2015. Constraints on the timescale of animal evolutionary history. Palaeontologia Electronica 18.1.1FC; 1-106; palaeo-electronica.org/content/fc-1 Calibrations published in the Fossil Calibration Series are accessioned into the Fossil Calibration Database (www.fossilcalibrations.org). The Database is a dynamic tool for finding up-to-date calibrations, and calibration data will be updated and annotated as interpretations change. In contrast, the Fossil Calibration papers are a permanent published record of the information on which the calibrations were originally based. Please refer to the Database for the latest data. BENTON ET AL.: ANIMAL HISTORY TIMESCALE