Vicariance and regionalization patterns in snakes of the South American Atlantic Forest megadiverse hotspot

Abstract

Aim Vicariance has often been invoked to explain bioregionalization patterns in the Neotropics. Using a revised point locality data for endemic species, we aimed to test for the first time the predictions of the vicariance model in shaping biogeographical regions for endemic snakes in the Atlantic Forest (AF) megadiverse hotspot. Location South American Atlantic Forest. Taxon Snakes (Reptilia, Serpentes). Methods To identify the non‐random groups of co‐distributed species, we mapped 21,101 point locality records in a grid cell of 0.5° × 0.5° across the AF, and constructed a presence–absence matrix of endemic species. The two major predictions of vicariance model were tested by Biotic Elements (BE) analysis, searching for groups of significantly co‐distributed species (Biotic Elements) by comparing distances between observed and artificial random ranges, produced under null models from Monte Carlo simulations. We also tested for the occurrence of sister species in different Biotic Elements, and compared our results with previous bioregionalization schemes revealed by other organisms in the AF. Results We recorded 252 species of snakes in the Atlantic Forest, of which 79 (31%) are endemic to this domain. Biotic Elements analysis with endemic species revealed seven clusters of co‐distributed species (BEs) corresponding to biogeographical regions. The significant non‐random clusters of geographical ranges revealed in BE analysis, and the distribution of sister species in different BEs, validated both central predictions of the vicariance model. Main conclusions Snakes defined non‐random biogeographical regions in the Atlantic Forest, and these were congruent with previously identified areas based on other groups of organisms, indicating that general processes influenced geographical ranges across the region. Both central predictions of the vicariance model were valid, indicating that vicariant events must have been important in shaping non‐random clusters of co‐distributed snakes in this biodiversity hotspot, harbouring some of the richest snake faunas on the planet.

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

“…Thus, a myriad of processes might have shaped their current diversity and geographic patterns. Despite the great endemism and diversity of this group in the Neotropical region [51], it is only recently that the biogeographic processes responsible for this diversity have started to be studied [52][53][54][55]. Snakes of the family Viperidae, also known as vipers, are distributed worldwide and comprise approximately 360 species [56].…”

The snake fauna of the most threatened region of the Atlantic Forest: natural history, distribution, species richness and a complement to the Atlas of Brazilian Snakes

“…Six centers of endemism or biogeographic subregions are currently known for snakes in the Atlantic Forest (Moura et al 2017;Barbo et al 2021), and the PEC is always recovered even with different methodologies. The PEC forests represent the northernmost center of endemism and the only one with a strong connection and geographical proximity with the Caatinga (Pereira- , assigning a very particular snake fauna to this region.…”

“…According to Nogueira et al (2019), there are 415 species of snakes in Brazil, and approximately 220 in the Atlantic Forest, representing 54.32% of all species (Moura et al 2017;Barbo et al 2021). A total of 86 species are recorded in the PEC, representing 43.09% of all species recorded in the Atlantic Forest.…”

“…A total of 86 species are recorded in the PEC, representing 43.09% of all species recorded in the Atlantic Forest. Considering the endemicity of the species, there are 79 endemic species in the whole biome, and 7 are endemic to the PEC forests: Micrurus potyguara, Bothrops muriciensis, Caaeteboia gaeli, Atractus caete, Atractus maculatus, Echinanthera cephalomaculata and Dendrophidion atlantica (Barbo et al 2021). These seven species are known from a few records in the PEC.…”

Climatic niche breadths of the Atlantic Forest snakes do not increase with increasing latitude

“…The Atlantic Forest is a complex morphoclimatic domain, including different ecological constraints and conditions throughout its range ( Olson et al 2001 ; Carnaval et al 2014 ). This region harbors a very diverse and highly endemic snake fauna, with at least 252 species, including 79 endemic snakes ( Barbo et al 2021 ). Carnaval et al (2014) demonstrated that climate variation affects the geographical distribution of endemic vertebrates in the Atlantic Forest, including amphibians, lizards, snakes, and Passeriformes.…”