Phylogenetics and diversification of whirligig beetles (Coleoptera, Gyrinidae)

Whirligig beetles are a family of aquatic beetles with an estimated 1,000 species distributed globally. Phylogenetic analysis incorporating molecular data has only recently been conducted on the family and many genera have never received modern taxonomic revision. The first chapter of the dissertation provides a taxonomic revision of the Southeast Asian whirligig beetle genus Porrorhynchus, finding the genus to contain 5 species, and no support for the numerous proposed subspecies. For the second chapter a phylogenetic analysis utilizing the most novel phylogenetic reconstructions methods incorporating the new Fossilized Birth-Death macroevolutionary model implemented in the program MrBayes 3.2.6 was conducted on the whirligig beetle tribe Dineutini. The analysis finds strong support for the monophyly of the tribe, and 4 out of 5 of the proposed genera. The numerous subgenera proposed for the genera Dineutus and Macrogyrus are unsupported, with most synonymized, and the remaining subgenera provided with new diagnoses and constituent species. The second chapter also includes a biogeographic analysis reconstructing the historical biogeography of the Dineutini. The third chapter utilizes the same phylogenetic methods as the second chapter, however, the analysis was performed at the family level, combining the dataset from a previous study as well taxa sampled in chapter two. The analysis reveals the whirligig beetles to be an ancient beetle group with Triassic origins, and the two currently monotypic subfamilies as the sole survivors of dominant clades from the Mesozoic