Resolving the evolutionary history of multiple groups of freshwater mussels (Bivalvia: Unionidae).

Abstract

Freshwater mussels are a group of aquatic invertebrates comprised of approximately one thousand species worldwide, and the greatest diversity of freshwater mussels lies within North America with at least three hundred species. The high level of biodiversity in this group is strongly shaped by a life history strategy that includes an obligate parasitic larval stage. Alarmingly, anthropogenic alterations to freshwater ecosystems have disproportionately impacted mussels as a group, resulting in freshwater mussels being one of the most imperiled groups of organisms on Earth, and global collaboration is needed to understand the factors contributing to their demise. Although considerable progress has been made in understanding ecology and evolution of freshwater mussels, the biology of many species is poorly understood and there remains a critical need for robust phylogenetic evaluation to understand the evolutionary history of many freshwater mussels. Genetic techniques have emerged as one of the most promising tools in understanding of the basic biological processes and dynamics of species; however, it is evident that integrating molecular data with multiple lines of evidence should be used to resolve evolutionary relationships. My dissertation research focuses on integrating robust phylogenetic evaluations with independent data types to resolve the evolutionary history and systematic relationships in multiple groups of North American freshwater mussels. My approach helped resolve numerous enigmatic questions pertaining to multiple groups of mussels, including accurately defining systematic placement, resolving species boundaries, and identifying functional traits that have driven lineage diversification. My findings have profound implications on the understanding of evolution and taxonomy, as well as illustrating the importance in incorporating multiple lines of evidence into phylogenetic assessments of freshwater mussels. As the scientific community continues to resolve the ecology and evolution of freshwater mussels globally, a firm understanding of species-specific traits will be critical toward determining conservation priorities and predicting species-specific responses in these highly imperiled organisms.