DISSERTATION RESEARCH: Phylogenomics and Evolutionary Rates associated with Salinity and Thermal Shifts in Centrarchiformes

Louisiana State University, Baton Rouge LA

Investigators

Abstract

Bony fishes are more diverse than any other class of vertebrates. However, we do not have a clear understanding of their history. Determining what led to this diversity will greatly help us understand how life has formed on our planet. It will also allow us to understand how future environmental perturbations might affect this diversity. Transitions to new habitat types, such as from freshwater to marine habitats, or tropical to temperate, may have increased fish diversity. Previous studies have examined the transition of fishes between these habitats and found varying amounts of support for the importance of each transition type. However, these transitions have only been examined in distantly related groups of fishes. This study will be the first to examine the evolutionary transitions between these habitats within a group of relatively closely related fish. These groups contain familiar and economically important species such as largemouth bass and sunfish. Outreach to the public and K-12 students will occur through presentations, social media, and museum displays. This project will take a novel approach to answer two macro-evolutionary questions: How have diversification rates in the Centrarchiformes varied between (1) tropical and temperate habitats and (2) between freshwater and marine habitats? To answer these questions phylogenetic relationships among Centrarchiform species will be resolved using dense taxonomic sampling and thousands of unlinked nuclear loci. The phylogeny will be fossil calibrated and used in a variety of analyses to test for shifts in the diversification rate and their potential associations with salinity or thermal habitat transitions. Furthermore, this project may provide general insight on the diversification of other aquatic groups that span diverse habitat types.