From Microevolutionary Processes to Macroevolutionary Patterns: Investigating Diversification at Multiple Scales in Southeast Asian Lizards

Abstract

A comprehensive understanding of the evolutionary processes responsible for generating biodiversity is best obtained using integrative approaches at multiple scales. In doing so, these investigations can provide complex insights into how fine-scale microevolutionary processes operating at the population level, translate into the large-scale macroevolutionary biodiversity patterns we see in evolutionary radiations. Due to the complex geography, historical climatic fluctuations, and remarkably high concentrations of land vertebrate biodiversity, Southeast Asia is an ideal place to investigate these processes. Lizards of the genus Eutropis represent one of the more recognizable radiations of lizards in Southeast Asia, due to their high abundances, broad geographic distribution, and generalized external morphology. However, their evolutionary history has remained enigmatic due to their highly conserved morphology and a lack of dense population sampling of individuals and species across their range. In this dissertation, I first utilize a variety of approaches to delimit species in Philippine Eutropis and find that species diversity is vastly underestimated by current taxonomy, while more generally assessing how best to determine species limits in radiations where morphology is highly conserved. I then use a molecular phylogenetic framework to investigate biogeographic patterns and the timing of diversification within the genus across Southeast Asia. Lastly, I take a landscape genomic approach to determine the relative contributions of distance, and various geographic and environmental variables to population genetic differentiation and morphological diversity patterns in the common sun skink. This research contributes substantially to our understanding of species diversity in evolutionary radiations, as well as how historical and contemporary evolutionary processes shape the evolution of morphological and genetic diversity.