Data from: Paleotemperatures and recurrent habitat shifts drive diversification of treefrogs across distinct biodiversity hotspots in sub-Amazonian South America

Aim: We investigate the biogeographic history and diversification in a
treefrog lineage distributed in contrasting (open and forested) ecoregions
of South America, including three biodiversity hotspots. We evaluate the
role of dispersal and whether other factors such as diversity-dependence
or paleotemperatures could explain the diversification pattern for this
group. Especially focusing on the savanna endemics, we illuminate on
processes governing the species assembly and evolution of the Cerrado
savanna. Location: South American ecoregions south of the Amazon (e.g.
Atlantic Forest, Cerrado, Araucaria Forest, Pampas, Central and Southern
Andes). Taxon: Boana pulchella group. Methods: We built the most complete
time-calibrated phylogeny for the group to date. We then reconstructed
ancestral ranges using the dispersal-extinction-cladogenesis (DEC) model
comparing different dispersal scenarios considering distance, adjacency
and ecological similarity among regions. A center-of-origin hypothesis in
forest versus open ecoregions was also tested. Using biogeographical
stochastic mapping, we additionally estimated the contribution of range
shifts across different biomes. Lastly, we evaluated several
diversification models, including the effect of time, diversity-dependence
and temperature-dependence on speciation and extinction rates. Results:
The Boana pulchella group originated during the Early Miocene (~17.5 MYA)
and underwent high speciation rates during the Middle Miocene Climatic
Optimum, with a decreasing trend following the Miocene Climatic
Transition. We found no support for a single ecoregion acting as a center
of origin and diversification; instead, we inferred recurrent range shifts
with dispersal among dissimilar adjacent ecoregions. Speciation linearly
dependent on paleotemperatures, with either no or very low constant
extinction rates, best explained the slowdown diversification pattern.
Main Conclusions: Our results support a species assembly of Cerrado
savanna in South America during the Miocene with intermittent interchange
with rainforest habitats. Past climate changes impacted the rate new
species originated with apparently no impact on extinction. Finally, the
repeated habitat shifts among open/dry and forested/humid ecoregions,
rather than long-term in-situ diversification in single areas, highlights
the very dynamic historical interchange between contrasting habitats in
South America, possibly contributing to its high species diversity.