Mosasaurid evolution: morphology, phylogeny, and paleobiology

Abstract

Mosasaurs are a group of lizards that entered the marine realm about 100 million years ago, evolved into highly marine adapted forms during their 34-million-year history, diversified to occupy a variety of feeding niches and habitats, and went extinct with the majority of life on Earth at the KPg boundary (~66Ma). As a group, they are a remarkable example of macroevolution, and especially that of secondarily adapted marine forms, mirroring the evolutionary history of whales. The latter part of their record (~85 MA-~66Ma) is relatively well represented, and relationships among those taxa are largely resolved, with lingering questions regarding the early evolutionary history of the group, especially their basal branching patterns, and their position within Squamata. Additionally, little is known of mosasaur feeding behavior. This thesis addresses some historically problematic phylogenetic relationships and also improves our understanding of the feeding biology of mosasaurs.