Dissertation Defense Announcement

Cristian Beza

for the Degree of Doctor of Philosophy

October 25, 2019 at 03:00 PM in Ellington Hall, Room 131

Advisor: Duane McKenna

Island biogeography in the continental New World tropics: Reconstructing the phylogeny and evolution of the Mesoamerican bess beetle tribe Proculini (Coleoptera: Passalidae)

ABSTRACT: The fauna of Mesoamerica is extraordinarily species rich and exhibits a high degree of local, regional and high-elevation endemism. Gaining an understanding of the historical biogeography and evolution of Mesoamerican endemics is necessary to develop strategies for the protection of regional biodiversity and sustainable use of natural resources in the region, as well as testing theories about the evolution of species diversity in tropical montane environments. I studied the distribution, evolution, and timing and patterns of diversification in Mesoamerican bess beetles in the tribe Proculini (Coleoptera, Passalidae). The high diversity of species and genera of Proculini in Mesoamerica is concentrated in montane environments, which contain many locally-endemic taxa. We reconstructed timing and patterns of Proculini diversification using nuclear DNA sequence data. We used the resulting phylogeny and time tree to obtain divergence time estimates and performed ancestral area reconstruction. The Proculini phylogeny included representatives of six of the eight tribes of Passalidae–we placed an emphasis on sampling the closely-related and species-rich New World tribes Passalini and Proculini. Our taxon sample included five of the six genera of Passalini, and all 20 known genera of Proculini, including a new genus discovered and described as part of this research. Our taxon sample included species from across the entire range of Proculini, from the Nearctic to Argentina, resulting in one of the most comprehensive phylogenies for a group of Neotropical insects. The divergence time analyses recovered a much older origin for Proculini than previously proposed and shows congruence between Proculini crown diversification and important paleogeographical events, e.g., K-Pg mass extinction, uplift and emergence of Mesoamerica from the sea during the Paleogene. Our data suggest Mesoamerica as a center of origin and taxonomic diversification of Proculini, contrasting with the traditional view of Mesoamerica as a transition zone between the Nearctic and South America.