UC Berkeley

In this thesis I use limb-reduced reptiles as a focal group to explore several largely ignored areas of inquiry in paleontology, herpetology, comparative anatomy, and macroecology. The convergence on limb-reduced or limbless body plans adapted for a burrowing lifestyle is a major theme in the evolution of squamate reptiles, but its implications for the anatomy, evolution, biogeography, and long-term success of clades are far from fully understood. Here, I develop novel techniques for understanding fossilization potential of extant species (Chapter 1), and understanding the evolution of surface patterns (Chapter 3), and apply these to limbless squamates to understand what information about their evolution might actually be available via the fossil record, and how scalation patterns may reflect their evolution and ecology. I address a major shortfall in the current understanding of the diversity of limbless squamates by constructing the first densely-sampled phylogeny of dibamid lizards (Chapter 2), and analyzing their diversity and biogeographic history. Finally, I use a microcosm of evolution, the island of Madagascar, as a test case to develop a comprehensive understanding of niche evolution and the role of specialization for fossoriality in shaping the biogeographic and diversification histories of fossorial reptiles (Chapter 4), plotting a path towards a comprehensive, global understanding of where, when, how, and why this body plan evolves, and what is possible for lineages after evolving this specialization.