DISSERTATION RESEARCH: Evaluating likelihood-based fossil-calibraition methods and timing of repeated incercontinental dispersal in a fossil-rich clade of Boraginaceae

化石通常被用作将系统发育假说校准到绝对时间的最可靠的方法。在测试想法之前，通常需要校准，例如史前事件的时间或特征的变化率。该项目研究了化石丰富的植物群隐花亚科（Boraginaceae），以测试两种最近提出但未经测试的将化石纳入系统发育分析的方法。在评估这些方法后，由此产生的时间校准的假设的系统发育关系将被用来检查新世界amphitrophic分离，在Cryptanthinae和许多其他组的植物，这可能是长距离传播的结果，由鸟类之间的北美和南美看到的分布模式。 该项目将对科学做出三大贡献。首先，评估新的方法，将化石数据纳入系统发育研究将有利于所有未来的研究使用化石数据。重要的是，这些方法可以推广到任何使用形态学数据的研究。第二，新世界两亲性间断是常见的，但研究不足。这项研究将测试目前关于这种地理模式的假设。最后，这个项目将产生一个假设的关系，在Cryptanthinae，将告知分类和保护在这个大的和生态上重要的植物群。

Fossils are routinely used as the most defensible method for calibrating phylogenetic hypotheses to absolute time. Calibration is often required before ideas can be tested, such as timing of a prehistoric event or rate of change of a trait. This project examines a fossil rich plant group, the Cryptanthinae (Boraginaceae), to test two recently proposed but untested methods for incorporating fossils in phylogenetic analyses. After evaluating these methods, the resulting time-calibrated hypothesis of phylogenetic relationships will be used to examine the New World amphitropical disjunction, a distribution pattern seen in the Cryptanthinae and many other groups of plants that is likely the result of long-distance dispersal by birds between North and South America. This project will result in three main contributions to science. First, evaluation of novel methods for incorporating fossil data into phylogenetic studies will benefit all future studies using fossil data. Importantly, these methods can be generalized to any study using morphological data. Second, New World amphitropical disjunction is common yet understudied. This study will test current hypotheses regarding this biogeographic pattern. Finally, this project will generate a hypothesis of relationships in the Cryptanthinae that will inform taxonomy and conservation in this large and ecologically important plant group.