title: Mammal body size evolution in North America and Europe over 20 Myr: similar trends generated by different processes.
abstract: Because body size interacts with many fundamental biological properties of a species, body size evolution can be an essential component of the generation and maintenance of biodiversity. Here we investigate how body size evolution can be linked to the clade-specific diversification dynamics in different geographical regions. We analyse an extensive body size dataset of Neogene large herbivores (covering approx. 50% of the 970 species in the orders Artiodactyla and Perissodactyla) in Europe and North America in a Bayesian framework. We reconstruct the temporal patterns of body size in each order on each continent independently, and find significant increases of minimum size in three of the continental assemblages (except European perissodactyls), suggesting an active selection for larger bodies. Assessment of trait-correlated birth-death models indicates that the common trend of body size increase is generated by different processes in different clades and regions. Larger-bodied artiodactyl species on both continents tend to have higher origination rates, and both clades in North America show strong links between large bodies and low extinction rate. Collectively, our results suggest a strong role of species selection and perhaps of higher-taxon sorting in driving body size evolution, and highlight the value of investigating evolutionary processes in a biogeographic context.
authors.affiliation: Senckenberg Biodiversity and Climate Research Centre (BiK-F), Frankfurt am Main, Germany shan.huang@senckenberg.de.
authors.forename: Shan
authors.identifier: 0000-0002-5055-1308
authors.initials: S
authors.lastname: Huang
authors.affiliation: Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.|BIOS Research Unit, Helsinki, Finland.
authors.forename: Jussi T
authors.initials: JT
authors.lastname: Eronen
authors.affiliation: Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Janis
authors.affiliation: Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.|Natural History Museum, London, UK.
authors.forename: Juha J
authors.initials: JJ
authors.lastname: Saarinen
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Daniele
authors.identifier: 0000-0003-0100-0961
authors.initials: D
authors.lastname: Silvestro
authors.affiliation: Senckenberg Biodiversity and Climate Research Centre (BiK-F), Frankfurt am Main, Germany.|Institute of Ecology, Evolution and Diversity, Goethe University, Frankfurt am Main, Germany.
authors.forename: Susanne A
authors.identifier: 0000-0002-4085-636X
authors.initials: SA
authors.lastname: Fritz
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D005075:Biological Evolution; D049628:Body Size; D005060:Europe; D008322:Mammals / Q000033:anatomy & histology*; D009656:North America; D010802:Phylogeny
keywords: Cope's rule; biogeography; diversification; higher-taxon sorting; species body mass; species selection