DISSERTATION RESEARCH: Testing Alternative Dispersal Routes for Neotropical Lowland Freshwater Fishes: Integration of Phylogeny, Physiology, and Geology

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The diverse freshwater fish fauna of Middle America (the region that includes (Mexico, Central America, and the Greater Antilles) has been tied to a myriad of notable biogeographic patterns; however, many of these patterns have not been rigorously examined. In cases where biogeographic patterns cannot be tied to geological events (e.g. the movement of tectonic plates) researchers often fall back on the untested hypothesis of marine dispersal. However, these freshwater species may not be crossing marine habitats or surviving in them for any length of time. This study will test marine dispersal hypotheses (by examining salt tolerance in these species) and raise a novel hypothesis for long distance dispersal in Middle America, namely river dispersal (a hypothesis that freshwaters and their fauna are periodically interconnected by periods of flooding). This study will take a new and integrative approach to unravel the biogeographic history of Neotropical lowland freshwater fishes with similar distributions in Middle America. Methods and data from physiology and geology will be used to vigorously test and distinguish between competing hypotheses. The river dispersal hypothesis could offer a new alternative explanation for the distribution of these fishes via dispersal through lowland rivers, and the results of this work could be used to explain and test the distributions of tropical freshwater species around the world.Undergraduate and underrepresented minority training is a major aspect of this work. Students will be involved in all aspects of this project from fieldwork, to publication, to presentation of these analyses at national and international meetings. The work will largely be conducted at the Louisiana State University Museum of Natural Science (LSUMNS), a research museum with numerous outreach activities through the university and local community. This study also has a large international component and participating scientists and students in these countries will be active participants in the research. In addition, all specimens and field data from their work will be deposited in the LSUMNS and will be readily available to researchers globally.