title: Terrestrial reproduction as an adaptation to steep terrain in African toads.
abstract: How evolutionary novelties evolve is a major question in evolutionary biology. It is widely accepted that changes in environmental conditions shift the position of selective optima, and advancements in phylogenetic comparative approaches allow the rigorous testing of such correlated transitions. A longstanding question in vertebrate biology has been the evolution of terrestrial life histories in amphibians and here, by investigating African bufonids, we test whether terrestrial modes of reproduction have evolved as adaptations to particular abiotic habitat parameters. We reconstruct and date the most complete species-level molecular phylogeny and estimate ancestral states for reproductive modes. By correlating continuous habitat measurements from remote sensing data and locality records with life-history transitions, we discover that terrestrial modes of reproduction, including viviparity evolved multiple times in this group, most often directly from fully aquatic modes. Terrestrial modes of reproduction are strongly correlated with steep terrain and low availability of accumulated water sources. Evolutionary transitions to terrestrial modes of reproduction occurred synchronously with or after transitions in habitat, and we, therefore, interpret terrestrial breeding as an adaptation to these abiotic conditions, rather than an exaptation that facilitated the colonization of montane habitats.
authors.affiliation: Department of Environmental Science (Biogeography), University of Basel, Klingelbergstrasse 27, 4056 Basel, Switzerland christoph.liedtke@ebd.csic.es.|Ecology, Evolution and Developmental Group, Department of Wetland Ecology, Estación Biológica de Doñana (CSIC), 41092 Sevilla, Spain.
authors.forename: H Christoph
authors.identifier: http://orcid.org/0000-0002-6221-8043
authors.initials: HC
authors.lastname: Liedtke
authors.affiliation: Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller-Universität Jena, Erbertstraße 1, 07743 Jena, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Müller
authors.affiliation: Department of Environmental Science (Biogeography), University of Basel, Klingelbergstrasse 27, 4056 Basel, Switzerland.|WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland.
authors.forename: Julian
authors.initials: J
authors.lastname: Hafner
authors.affiliation: Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, 10115 Berlin, Germany.|Chair of Wildlife Ecology and Management, University of Freiburg, Tennenbacher Straße 4, 79106 Freiburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Penner
authors.affiliation: Department of Life Sciences, Natural History Museum, London SW7 5BD, UK.
authors.forename: David J
authors.identifier: http://orcid.org/0000-0002-1725-8863
authors.initials: DJ
authors.lastname: Gower
authors.affiliation: Dříteč 65, 53305, Czech Republic.
authors.forename: Tomáš
authors.initials: T
authors.lastname: Mazuch
authors.affiliation: Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, 10115 Berlin, Germany.
authors.forename: Mark-Oliver
authors.initials: MO
authors.lastname: Rödel
authors.affiliation: Department of Environmental Science (Biogeography), University of Basel, Klingelbergstrasse 27, 4056 Basel, Switzerland.|Department of Life Sciences, Natural History Museum, London SW7 5BD, UK.|Department of Life Sciences, University of Roehampton, London SW15 4JD, UK.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Loader
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002025:Bufonidae / Q000502:physiology*; D004777:Environment; D010802:Phylogeny; D012098:Reproduction
keywords: Bufonidae; amphibian; evolution; reproductive mode; terrestrial life history; viviparity