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

中美洲（该地区包括墨西哥、中美洲和大安的列斯群岛）的淡水鱼区系的多样性与无数著名的生物地理模式有关；然而，这些模式中的许多都没有经过严格的检验。在生物地理模式不能与地质事件联系起来的情况下（例如，构造板块的运动），研究人员往往依赖于未经检验的海洋扩散假说。然而，这些淡水物种可能不会穿越海洋栖息地，也不会在其中存活一段时间。这项研究将测试海洋扩散假说（通过检查这些物种的耐盐性），并提出中美洲长距离扩散的新假说，即河流扩散（假设淡水和它们的动物群在洪水期间周期性地相互联系）。本研究将采用一种新的综合方法来揭示中美洲具有相似分布的新热带低地淡水鱼类的生物地理历史。生理学和地质学的方法和数据将用于有力地检验和区分相互竞争的假设。河流扩散假说可以为这些鱼类通过低地河流扩散的分布提供一种新的替代解释，这项工作的结果可以用来解释和测试世界各地热带淡水物种的分布。本科生和未被充分代表的少数民族培训是这项工作的主要方面。学生将参与该项目的各个方面，从实地考察到出版，再到在国内和国际会议上介绍这些分析。这项工作将主要在路易斯安那州立大学自然科学博物馆（LSUMNS）进行，这是一个通过大学和当地社区开展大量外展活动的研究博物馆。这项研究也有很大的国际组成部分，这些国家的参与科学家和学生将积极参与研究。此外，他们工作的所有标本和现场数据将储存在LSUMNS中，并将随时供全球研究人员使用。

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.