SGER: Morphological CT Scan of Notropis megalepis for Phylogenetic and Evolutionary Studies

从历史上看，北美太阳鱼和小鱼和银鱼物种之间在多样性方面的鲜明对比是研究两个相同年龄组(基于化石记录)不同进化速度的肥沃研究领域。对骨学特征的分支分析揭示了以前这种性质的研究和这些鱼的分类的根本缺陷，从而质疑了以前的进化研究的准确性。如今，由于PI及其合作者以及其他研究人员的最新形态和分子分析，Notrois(Shiners)及其近缘物种的系统发育关系相对较好。利用形态和分子数据也将很快获得的中心鱼科物种的关系，将提供必要的信息，以开始太阳鱼和银鱼群体之间的比较研究，正如早期研究人员所设想的那样-进化中的等级异质性。然而，在推进这项研究的过程中仍然存在一个值得注意的问题，那就是将用于确定诺特罗伊斯血统的物种巨型诺托罗非鱼的系统发育位置归入一个适合比较的支系。PI建议使用由Tim Rowe博士维护的德克萨斯大学NSF多用户设施开发的最新技术，对堪萨斯州西部上新世中期的巨型诺托罗西斯化石进行高分辨率CT扫描。这块化石是测定其所属的北美闪光鱼和小鱼群体的年龄和评估这两类鱼类进化速度异质性的基础。对进化关系的准确估计对于信息检索和生物预测的整体框架是必要的。这种信息和可预测性的用途包括跟踪疾病的起源，确定入侵物种的生物防治制剂，以及评估与生物保护有关的风险因素。

Historically, the stark contrast in diversity between North America's sunfish and minnow and shiner species served as a fertile research area for studying differential rates of evolution in two groups of equal age (based on fossil record). Cladistic analyses of osteological characters revealed fundamental flaws with previous studies of this nature and classifications of these fishes, thus questioning the accuracy of prior evolutionary studies. Today, phylogenetic relationships of species of Notropis (shiners) and relatives are relatively well known due to recent morphological and molecular analyses by the PI and collaborators as well as other researchers. Relationships of species of Centrarchidae, also soon to be available using morphological and molecular data, will provide the necessary information to begin comparative studies between the sunfish and shiner groups as envisioned by earlier researchers - rate heterogeneity in evolution. However, a notable problem remaining in advancing this research is the phylogenetic placement of the species Notropis megalepis, the species used to date the Notropis lineage, to a clade appropriate for comparison. The PI proposes to conduct high-resolution CT scans of the fossil Notropis megalepis from the Middle Pliocene of western Kansas using the recent technology developed at The University of Texas NSF Multi-user facility maintained by Dr. Tim Rowe. This fossil is fundamental in dating the age of the North American shiner and minnow group to which it belongs and evaluating rate heterogeneity in evolution for these two groups of fishes. Producing accurate estimates of evolutionary relationships is necessary for the overall framework for information retrieval and biological prediction. Uses of such information and predictability include tracking the origins of disease, identifying biological control agents for invasive species, and evaluating risk factors associated with biological conservation.