| Summary: | The lizard family Scincidae is the most species-rich family of squamate reptiles, comprising more than 1,600 species. Skinks are ecologically and morphologically diverse, occurring in tropical and temperate zones on all continents excluding Antarctica, as well as on many oceanic islands. Although skinks are a ubiquitous part of most of the world’s herpetofauna, we still lack a basic understanding of the evolutionary history and biodiversity of many clades within the family. Using molecular data, concatenated- and coalescent-based phylogenetic analyses, morphological datasets, and multivariate statistics, I reconstruct the evolutionary history of a clade of skinks called the Lygosoma group skinks, a group of elongate-bodied semifossorial species distributed across the Old World tropics in Africa, South Asia, Southeast Asia, and Sundaland. My dissertation focuses on the phylogenetics, systematics, taxonomy, species-level diversity, and biogeography of this group, and I address questions including: How are species related? What macroevolutionary factors have influenced species diversification across evolutionary time? And, how have historical processes shaped the modern biodiversity of Lygosoma group skinks? Additionally, I use high speed videos of locomotion and multivariate statistics to investigate the locomotor kinematics and performance of three species of co-distributed skinks in Thailand to address the following question: Does diversity in morphology result in diversity in locomotor performance and kinematics? The results of my dissertation provide insight into the evolutionary history and biodiversity of skinks in the Old World tropics. In my first chapter, I delve into the taxonomic history of Lygosoma group skinks and propose a new classification based on phylogeny generated with the most robust genetic and taxonomic sampling of the group to date. The genera Lepidothyris, Lygosoma and Mochlus comprise the writhing or supple skinks (Lygosoma s.l.), a group of semi-fossorial, elongate-bodied skinks ...
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