title: Dating Tips for Divergence-Time Estimation.
abstract: The molecular clock is the only viable means of establishing an accurate timescale for Life on Earth, but it remains reliant on a capricious fossil record for calibration. 'Tip-dating' promises a conceptual advance, integrating fossil species among their living relatives using molecular/morphological datasets and evolutionary models. Fossil species of known age establish calibration directly, and their phylogenetic uncertainty is accommodated through the co-estimation of time and topology. However, challenges remain, including a dearth of effective models of morphological evolution, rate correlation, the non-random nature of missing characters in fossil data, and, most importantly, accommodating uncertainty in fossil age. We show uncertainty in fossil-dating propagates to divergence-time estimates, yielding estimates that are older and less precise than those based on traditional node calibration. Ultimately, node and tip calibrations are not mutually incompatible and may be integrated to achieve more accurate and precise evolutionary timescales.
authors.affiliation: School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: O'Reilly
authors.affiliation: Department of Genetics, Evolution and Environment, University College London, London, WC1E 6BT, UK; Present address: School of Biological and Chemical Sciences, Queen Mary, University of London, London, E1 4NS, UK.
authors.forename: Mario
authors.initials: M
authors.lastname: Dos Reis
authors.affiliation: School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK. Electronic address: phil.donoghue@bristol.ac.uk.
authors.forename: Philip C J
authors.initials: PCJ
authors.lastname: Donoghue
mesh_terms: D000818:Animals; D002138:Calibration; D019143:Evolution, Molecular; D053476:Extinction, Biological; D005580:Fossils; D049810:Genetic Speciation; D019015:Geologic Sediments; D006927:Hymenoptera / Q000033:anatomy & histology / Q000145:classification / Q000235:genetics*; D015233:Models, Statistical; D013997:Time Factors; D035501:Uncertainty