DISSERTATION RESEARCH: Why species delimitation matters: Cryptic diversity, complete species-level phylogeny, and Andean diversification of an American marsupial clade

新热带地区是世界上生物多样性最丰富的地区之一。然而，了解这种多样性背后的历史过程是一项具有挑战性的任务，部分原因是该地区复杂的地理和气候历史。对于哺乳动物来说，由于我们缺乏对生物多样性的基本知识，比如在这个地区出现的物种数量、它们的分布以及它们之间的关系，这项任务进一步受到阻碍。对于一组小负鼠（Thylamyini）来说尤其如此，它们广泛分布在整个新热带地区，但在形态上往往彼此难以区分。目前已知的Thylamyini有37种，但初步分析表明，物种多样性可能几乎是这个数字的两倍。该项目旨在利用多个核和线粒体DNA序列以及形态学来发现这一生态重要哺乳动物群体的真正多样性。这一修正的哺乳动物多样性观点将对我们对新热带动物多样性的理解产生深远的影响，并将为在全球灭绝的时代急需的保护策略提供基础。此外，拟议的外展和教育活动将继续加强美国和哥伦比亚高等教育机构之间的发展合作。

The Neotropics is one of the most biodiverse regions of the world. However, understanding the historical processes underlying this diversity is a challenging task due in part to the complex geographic and climatological history of this region. For mammals, this task is further hindered by our lack of fundamental knowledge about biodiversity, such as the number of species occurring in this area, their distribution, and how they are related to each other. This is particularly true for a group of small opossums (Thylamyini), which are broadly distributed throughout the Neotropics but are often morphologically indistinguishable from each other. There are 37 currently recognized species of Thylamyini, but preliminary analyses suggest that species diversity may be nearly double that. This project aims to discover the true diversity of this ecologically important group of mammals using multiple nuclear and mitochondrial DNA sequences as well as morphology. This revised view of mammalian diversity will have profound implications for our understanding of diversification in the Neotropics and will provide the basis for much needed conservation strategies in this time of global extinction. In addition, the proposed outreach and educational activities will continue to strengthen developing collaborations between US and Colombian institutions of higher education.