DISSERTATION RESEARCH: Fossils, fruits, and phylogeny: an integrative approach to understanding the historical biogeography of palms over the last 100 million years

棕榈树在世界各地的热带地区都有大量的发现，在生态系统和全球经济中发挥着重要作用。从进化和环境的角度来看，棕榈是一组有趣的植物。它们有着悠久的进化历史，至少可以追溯到9000万年前，有丰富而广泛的化石记录为证，并且由于大多数物种可以生存的气候范围很窄，因此它们是过去环境条件的有用指标。通过使用化石记录来了解棕榈树的进化历史，这项研究试图了解它们的地理范围，以及它们在整个历史中如何应对不断变化的环境。这项研究将测试目前关于棕榈进化的假设，并生成公开的活棕榈和化石棕榈多样性数据库。一名研究生将接受不同系统学方法的培训，这项研究产生的数据集也将用于培训来自代表性不足群体的本科生。研究材料还将用于开发互动展览，用于向公众讲授植物结构、多样性和进化。本项目通过将地质记录的经验数据纳入系统发育和基于模型的植物地理分析，研究棕榈科的历史植物地理。它将测试目前的假设，一个劳亚起源的冠节槟榔科和主要亚科的地理起源。这项工作还将调查变化的大陆地理在棕榈树辐射中的作用，以及气候变化如何与过去1亿年来的扩散和灭绝率变化相关。将编制一个棕榈化石记录的综合数据库，并将数据纳入扩散-灭绝-分支发生模型，以推断分类群的历史范围，并纳入扩散-灭绝-取样模型，以计算随时间推移的扩散和灭绝率，这可以与气候数据相关联。化石水果有足够的字符，包括在系统发育分析将使用X射线显微计算机断层扫描进行研究，并将用于产生一个时间校准的系统发育用于DEC分析。成果包括一个全面的棕榈化石记录数据库，活棕榈的3D形态数据，家族的部落级年表，以及对这一重要植物群历史地理学的新见解。

Palms are found abundantly throughout tropical regions worldwide and have important roles in ecosystems and the global economy. Palms are an interesting group of plants from both an evolutionary and environmental perspective. They have a long evolutionary history stretching back at least 90 million years, evidenced by a rich and widespread fossil record, and are useful indicators of past environmental conditions due to the narrow climatic range within which most can survive. By using the fossil record to inform the evolutionary history of palms, this research seeks to understand their geographical range, and how they have responded to changing environments throughout their history. This research will test current hypotheses on palm evolution, and generate publicly available databases of living and fossil palm diversity. One graduate student will be trained in diverse systematics methods, and datasets generated by this research will also be used to train undergraduates from underrepresented groups. Materials from the research will also be used to develop interactive exhibits for teaching about plant structure, diversity, and evolution to the public.This project investigates the historical biogeography of the palm family by incorporating empirical data from the geologic record into phylogenetic and model-based biogeographic analyses. It will test current hypotheses of a Laurasian origin of the crown node of Arecaceae and of the biogeographic origins of the major subfamilies. This work will also investigate the role of shifting continental geography in the radiation of palms, and how climatic changes correlate with shifts in dispersal and extinction rates over the last 100 million years. A comprehensive database of the palm fossil record will be compiled and the data incorporated into a dispersal-extinction-cladogenesis (DEC) model to infer historical ranges of taxa, and a dispersal-extinction-sampling model to compute dispersal and extinction rates over time, which can be correlated with climate data. Fossil fruits with sufficient characters for inclusion in a phylogenetic analysis will be studied using X-ray micro-computed tomography, and will be used to generate a time-calibrated phylogeny for use in the DEC analysis. Outcomes include a comprehensive fossil record database for palms, 3D morphological data on living palms, a tribe-level chronogram for the family, and new insights into the historical biogeography of this important group of plants.