title: Animal Evolution: Only Rocks Can Set the Clock.
abstract: Molecular clocks have become the method of choice to date the tree of life. A new study demonstrates that there are limits to their precision, which may only be overcome by improving our knowledge of the fossil record.
authors.affiliation: School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK; School of Earth Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK. Electronic address: Davide.Pisani@bristol.ac.uk.
authors.forename: Davide
authors.initials: D
authors.lastname: Pisani
authors.affiliation: School of Earth Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK.
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Liu
mesh_terms: D000818:Animals; D005075:Biological Evolution; D019143:Evolution, Molecular; D005580:Fossils; D010802:Phylogeny