Data from: The origins and diversification of the exceptionally rich gemsnakes (Colubroidea: Lamprophiidae: Pseudoxyrhophiinae) in Madagascar
Burbrink, Frank et al. (2019), Data from: The origins and diversification of the exceptionally rich gemsnakes (Colubroidea: Lamprophiidae: Pseudoxyrhophiinae) in Madagascar, Dryad, Dataset, https://doi.org/10.5061/dryad.07h0n14
Processes leading to spectacular diversity of both form and species on islands have been well documented under island biogeography theory, where distance from source and island size are key factors determining immigration and extinction resistance. Less understood are the processes governing in-situ diversification on the world’s mega islands, where large and isolated land masses produced morphologically distinct radiations from related taxa on continental regions. Madagascar has long been recognized as a natural laboratory due to its isolation, lack of influence from adjacent continents, and diversification of spectacular vertebrate radiations. However, only a handful of studies have examined rate shifts of in-situ diversification for this island. Here we examine rates of diversification in the Malagasy snakes of the family Pseudoxyrhophiinae (gemsnakes) to understand if rates of speciation were initially high, enhanced by diversification into distinct biomes, and associated with key dentition traits. Using a genomic sequence-capture dataset for 366 samples, we determine that all previously described and newly discovered species are delimitable and therefore useful candidates for understanding diversification trajectories through time. Our analysis detected no shifts in diversification rate between clades or changes in biome or dentition type. However, we did detect a significant slowdown in diversification during the Pleistocene. We comment on the apparent paradox where most living species originated in the Pleistocene, yet diversification rates were highest during the previous 15 million years.