title: Climate-mediated diversification of turtles in the Cretaceous.
abstract: Chelonians are ectothermic, with an extensive fossil record preserved in diverse palaeoenvironmental settings: consequently, they represent excellent models for investigating organismal response to long-term environmental change. We present the first Mesozoic chelonian taxic richness curve, subsampled to remove geological/collection biases, and demonstrate that their palaeolatitudinal distributions were climate mediated. At the Jurassic/Cretaceous transition, marine taxa exhibit minimal diversity change, whereas non-marine diversity increases. A Late Cretaceous peak in 'global' non-marine subsampled richness coincides with high palaeolatitude occurrences and the Cretaceous thermal maximum (CTM): however, this peak also records increased geographic sampling and is not recovered in continental-scale diversity patterns. Nevertheless, a model-detrended richness series (insensitive to geographic sampling) also recovers a Late Cretaceous peak, suggesting genuine geographic range expansion among non-marine turtles during the CTM. Increased Late Cretaceous diversity derives from intensive North American sampling, but subsampling indicates that Early Cretaceous European/Asian diversity may have exceeded that of Late Cretaceous North America.
authors.affiliation: Department of Earth Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK.
authors.forename: David B
authors.identifier: http://orcid.org/0000-0002-1296-5673
authors.initials: DB
authors.lastname: Nicholson
authors.affiliation: Museum of Paleontology, University of California, 1101 Valley Life Sciences Building, Berkeley, California 94720, USA.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Holroyd
authors.affiliation: Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK.
authors.forename: Roger B J
authors.initials: RBJ
authors.lastname: Benson
authors.affiliation: Department of Earth Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Barrett
mesh_terms: D000818:Animals; D001208:Asia; D044822:Biodiversity; D005075:Biological Evolution; D057231:Climate Change; D005060:Europe; D005580:Fossils; D009656:North America; D014426:Turtles