THE EFFECT OF HABITAT ON DIVERSIFICATION RATE IN SNAKES

The first snakes originated during the Mesozoic era (140-150 Ma) and have since flourished in richness to over 3400 species today. Snakes have evolved to fill ecological niches across multiple habitats. The purpose of this study was to investigate whether the occupation of those habitats has had an impact on the rate of accumulation of snake species since their origin. To test for differences in diversification rate among multiple habitats, we collected data on the occupation of eight unique habitats for 1610 extant snake species from existing databases, regional guides, and primary literature. We combined these new data with preexisting life history and environmental data on snakes to create a comprehensive ecophysiological dataset. Using a preexisting snake phylogeny, we then estimated diversification rates on RStudio with two commonly used techniques: Equal Splits and BAMM (Bayesian Analysis of Macroevolutionary Mixtures). Both methods indicate that snakes living in aquatic habitats have higher diversification rates than snakes living in either semi-aquatic or terrestrial habitats. Specifically, those living in marine habitats exhibit significantly increased diversification rates. Environmental temperature data for a subset of these marine snakes indicate that they are constrained to very warm water (> 25°C), possibly due to energetic constraints that may also influence diversification rates.