DISSERTATION RESEARCH Fossils and phylogeny: investigating the timing of diversification in a diverse lineage of Neotropical rodents (Caviomorpha: Octodontoidea)

生物多样性模式是物种形成和灭绝等历史过程的产物，但现存物种只保存了这一历史的一部分。具有可靠化石记录和多样化生态和生物地理辐射的谱系提供了更好的见解。这个项目的重点是这样一个谱系，八齿纲（degus和它们的亲戚）。这些啮齿动物种类繁多（6科193种），遍布新热带地区，它们的化石记录可以追溯到渐新世（78个化石属）。该项目将研究这些啮齿动物多样化的模式、时间和速率，方法是将化石及其地质年代的信息与现存物种的DNA序列相结合。这些数据将用于为该群体的进化产生一个时间假设，然后用于研究历史和生态因素如何影响进化速度。该项目为保护生物多样性提供了理论见解和实践信息，因为许多活的八齿鲨受到威胁或濒临灭绝。在芝加哥菲尔德博物馆进行这项研究将有助于向国际观众推广；结果将显示在博物馆DNA发现中心的数字触摸屏上，并通过教育和会员部门的项目共享。除了为研究生提供关键培训外，这笔赠款还将有助于建立生物多样性和遗传数据存储的公共数据库。

Biodiversity patterns are products of historical processes such as speciation and extinction, but living species preserve only part of this history. Lineages with robust fossil records and diverse ecological and biogeographic radiations offer greater insights. This project focuses on one such lineage, the Octodontoidea (degus and their relatives). These rodents are diverse (193 species across six families), found throughout the Neotropics, and their fossil record extends back to the Oligocene (78 fossil genera). This project will investigate the patterns, timing, and rates of diversification of these rodents by integrating information from fossils and their geologic ages with DNA sequences from living species. These data will be used to generate a temporal hypothesis for the group's evolution that will then be used to examine how historical and ecological factors have influenced evolutionary rates over time. This project offers theoretical insights and practical information for conserving biodiversity, as many living octodontoids are threatened or endangered. Conducting this research at Chicago's Field Museum will facilitate outreach to an international audience; results will appear on a digital touch-screen in the Museum's DNA Discovery Center and shared through programs in the Education and Membership departments. Besides providing key training to a graduate student, this grant will contribute to public databases where biodiversity and genetic data will be deposited.