The role of vicariance and dispersal on the temporal range dynamics of forest vipers in the Neotropical region

Conserving biogeographical units of endemic amphibians in the megadiverse Atlantic Forest

The initial step in many biogeography approaches involves identifying biogeographical units, which serve as fundamental building blocks for understanding biodiversity patterns and guiding conservation efforts. We aimed to analyse the conservation of biogeographical units of an endangered biodiversity hotspot by: (i) detecting clusters of endemic frog species; (ii) testing predictions of vicariance model; (iii) evaluating the conservation of the patterns based on protected areas and habitat loss; and (iv) highlighting priority biogeographical units for conservation. Biogeographical units were identified via Biotic Elements analysis, using range polygons for 381 endemic frogs. We tested two predictions of vicariance model: (i) the occurrence of non-random patterns, forming clusters of co-occurring species (Biotic Elements, BEs); and (ii) the occurrence of closely related species in distinct BEs. We calculated the percentage of forest remnants in each BE and their overlap with protected areas. We highlighted those with high degrees of irreplaceability and/or vulnerability as priority BEs for conservation. We recovered 21 Biotic Elements. Both predictions of the vicariance model were validated. On average, BEs presented 28% of forest remnants, but only 12% of their total areas were protected. Mountain ranges of central Atlantic Forest harbour most of BEs, emphasizing the importance of safeguarding these regions.

Marine introgressions and Andean uplift have driven diversification in neotropical Monkey tree frogs (Anura, Phyllomedusinae)

The species richness in the Neotropics has been linked to environmental heterogeneity and a complex geological history. We evaluated which biogeographic processes were associated with the diversification of Monkey tree frogs, an endemic clade from the Neotropics. We tested two competing hypotheses: the diversification of Phyllomedusinae occurred either in a "south-north" or a "north-south" direction in the Neotropics. We also hypothesized that marine introgressions and Andean uplift had a crucial role in promoting their diversification. We used 13 molecular markers in a Bayesian analysis to infer phylogenetic relationships among 57 species of Phyllomedusinae and to estimate their divergence times. We estimated ancestral ranges based on 12 biogeographic units considering the landscape modifications of the Neotropical region. We found that the Phyllomedusinae hypothetical ancestor range was probably widespread throughout South America, from Western Amazon to Southern Atlantic Forest, at 29.5 Mya. The Phyllomedusines' ancestor must have initially diverged through vicariance, generally followed by jump-dispersals and sympatric speciation. Dispersal among areas occurred mostly from Western Amazonia towards Northern Andes and the South American diagonal of dry landscapes, a divergent pattern from both "south-north" and "north-south" diversification hypotheses. Our results revealed a complex diversification process of Monkey tree frogs, occurring simultaneously with the orogeny of Northern Andes and the South American marine introgressions in the last 30 million years.