Phylogenetics, biogeography, and evolution of fishes

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This research uses DNA sequences to reconstruct evolutionary history, with the aim of understanding how species diversify in the natural world. We focus on a group of fishes from South America, the gymnotiform knifefishes, that can produce and detect minute electrical fields using highly specialized electric organs and electroreceptors. These electric fields are used for both navigation and communication, and electric knifefishes can operate quite normally in total darkness. Also, different species of knifefishes have different electric signals, suggesting that species recognize each other using their signals. To understand how the 200 species of gymnotiform knifefishes have evolved, we are building evolutionary trees using nuclear and mitochondrial gene sequences. These evolutionary trees will be used to understand the role of geography in promoting speciation, as well as how electric signals evolve when speciation occurs. The results of this study have relevance for evolutionary biology and ecology, as well as for neurobiology, where gymnotiform knifefishes are important model organisms. By studying the biodiversity of fishes, we provide valuable data for conservation biology.