Data from: Terrestrial reproduction as an adaptation to steep terrain in African toads

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.