Phylogenetics, biogeography, and evolution of fishes

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The central focus of my research program is to investigate evolutionary patterns and processes of biodiversity in fishes. I use phylogenetic trees as invaluable tools for understanding taxonomy and species diversity, the effects of geography and paleogeography on lineage diversity, macroevolutionary consequences of shifts between habitat types, and adaptive evolutionary change in novel anatomical systems. In the work proposed here, my research group will infer phylogenetic relationships for two groups of fishes: the drum (Sciaenidae) and the Neotropical electric knifefishes (Gymnotiformes). Phylogenetic trees for these groups will form a basis for understanding the evolution of aquatic habitat transitions, and the evolution of electricity as a sensory modality.****The drum (Sciaendiae) are a globally-distributed family of fishes that are mainly marine, but include endemic freshwater species in North America, South America, and Asia. These fishes are an excellent model system for studying the evolution of transitions between marine and freshwater habitats. To reconstruct the evolutionary history of drum, we will build a phylogenetic tree using targeted sequence capture and next-generation DNA sequencing to sample approximately 1000 genes. We will use the phylogeny to test hypotheses about how marine to freshwater habitat transitions alter lineage and morphological diversification patterns. We will also leverage the large amounts of collected DNA sequence data to examine the evolution of genes involved in osmoregulation and visual adaptation to new environments. This research will illuminate how transitions between habitats affect evolution at large spatial and temporal scales.****The electric knifefishes (Gymnotiformes) are an order of neotropical fishes that use electricity for communication and navigation. Because their electric sigals are amenable to quantification and analysis, gymnotiforms are an important model system for neurobiology and behavioural studies. However, evolutionary relationships among gymnotiform species are poorly understood. My lab will reconstruct the phylogenetic relationships of this group by using targeted sequence capture. Using a large library of communication signal data accumulated over the past decade, we will test the hypothesis that natural selection to avoid mismating drives evolution of signal divergence. Using genetic data produced by sequence capture, we will examine rates and patterns of evolution in genes associated with electric signal production. This work will clarify how communication signals evolve, and provide a framework for a variety of long-term studies on this important group of fishes.****This research will provide training for undergraduate and graduate students in biodiversity, molecular systematics, and evolutionary biology, and will contribute to fundamental knowledge of evolutionary patterns and processes.**