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

Abstract

The emergence of the diagonal of open/dry vegetations, including Chaco, Cerrado and Caatinga, is suggested to have acted as a dispersal barrier for terrestrial organisms by fragmenting a single large forest that existed in South America into the present Atlantic and Amazon forests. Here we tested the hypothesis that the expansion of the South American diagonal of open/dry landscapes acted as a vicariant process for forest lanceheads of the genus Bothrops, by analyzing the temporal range dynamics of those snakes. We estimated ancestral geographic ranges of the focal lancehead clade and its sister clade using a Bayesian dated phylogeny and the BioGeoBEARS package. We compared nine Maximum Likelihood models to infer ancestral range probabilities and their related biogeographic processes. The best fitting models (DECTS and DIVALIKETS) recovered the ancestor of our focal clade in the Amazon biogeographic region of northwestern South America. Vicariant processes in two different subclades resulted in disjunct geographic distributions in the Amazon and the Atlantic Forest. Dispersal processes must have occurred mostly within the Amazon and the Atlantic Forest and not between them. Our results suggest the fragmentation of a single ancient large forest into the Atlantic and Amazon forests acting as a driver of vicariant processes for the snake lineage studied, highlighting the importance of the diagonal of open/dry landscapes in shaping distribution patterns of terrestrial biota in South America.

Historical biogeography of neotropical Monkey tree frogs (Anura: Phyllomedusidae) indicates a diversification driven by dispersal and sympatry

“…In accordance with the ndings for several other groups in Metazoa (e.g., Dal Vechio et al, 2018;Pontes-Nogueira et al, 2021;Prates et al, 2017), our results on DECTS + j model suggest Western Amazonia acted as a species pump for phyllomedusid frogs. Western Amazonia was recovered as ancestral area for clades (Phyllomedusa (Callimedusa + Pithecopus)), Callimedusa + Pithecopus, for the genera Phyllomedusa, Callimedusa and Pithecopus and for the split between Phasmahyla and the clade (Phyllomedusa (Callimedusa + Pithecopus)).…”

“…Most studies examining the processes leading to biota diversi cation in the Neotropics focus on ecologically or geographically restricted groups (e.g., Guarnizo et al, 2016;Smith et al, 2014;Werneck et al, 2015), in a localscale approach. Instead, studies focusing on widespread clades could elucidate the role of multiple of the processes over space and deep time, contributing to create a macroevolutionary framework (e.g., Hamdan et al, 2019;Pontes-Nogueira et al, 2021;Prieto-Torres et al, 2019;Vicente et al, 2017), given the complex dynamic of biogeography in Neotropical region. Among anurans, this scenario ts well for Phyllomedusidae, a family virtually occurring throughout the entire Neotropics.…”

There and back again: when and how the world’s richest snake family (Dipsadidae) dispersed and speciated across the Neotropical region

“…An increasing geographical and genetic isolation likely occurred for species with cross-Andean distributions imposed by Andean uplift that subsequently led to a pattern of coeval cis-Andean/trans-Andean vicariant events in Dipsadidae -within the Atractus genus at 11 mya, as previously suggested (Passos, Lynch & Fernandes, 2008) -and in Xenondontinae, in the Siphlophis genus (~8 mya), as well as for Neotropical pitvipers (Pontes-Nogueira, Martins, Alencar & Sawaya, 2021). The Andean uplift may have indirectly contributed to speciation by altering climate and environment in pan-Amazonia (Hoorn et al, 2010), as such events have been shown to be strong drivers of diversification in the region (Pinto-Ledezma, Simon, Diniz-Filho & Villalobos, 2017;Rangel et al 2018;Vasconcelos et al, 2020), especially for ectotherms (Santos, Coloma & Summers, 2009;Esquerré, Brennan, Catullo, Torres-Pérez & Keogh, 2019;Meseguer et al, 2021).…”

There and back again: when and how the world's richest snake family (Dipsadidae) dispersed and speciated across the Neotropical region

“…Historical biogeography (Posadas et al, 2006) is an essential tool to understand the origin and composition of current Neotropical biotas such as snake assemblages since biogeographical processes such as dispersal, vicariance and extinction strongly influence local and regional biodiversity through time (Crisci, 2001;Moritz et al, 2000;Ricklefs, 1987). However, comprehensive studies on Neotropical historical biogeography have been severely hampered by the lack of detailed phylogenetic hypotheses and distributional data (Bagley & Johnson, 2014) as well as analytical limitations (Landis et al, 2013;Matzke, 2013).…”