Reevaluation of 'Friasian' mammal faunas from Argentina, Bolivia, and Chile

对阿根廷、玻利维亚和智利的菲拉斯哺乳动物动物群的重新评估凯斯西储大学达林·克罗夫特南美洲大约80%的地区位于热带，赤道两侧的低纬度地区，包括热带雨林、沙漠和各种其他栖息地。这片广阔的新热带地区拥有南美洲大部分生物多样性，以及整个地球生物多样性的很大一部分。人类越来越多地入侵新热带地区，以及气候变化等其他因素，使该地区成为最优先保护的地区。但是，保护这种生物多样性的最佳战略是什么，不仅是现在的生物多样性，而且是未来的生物多样性？回答这个问题的一种方法是研究古代生物多样性的模式，以更好地了解在特定时间特定地点影响物种数量和类型的因素。我们的项目将采取这样的方法，调查新热带群落中一些最重要和最引人注目的成员：哺乳动物的进化和生物地理历史。特别是，我们将讨论关于南美洲现代哺乳动物群落在过去2000万年中如何发展的三个假说：(1)哺乳动物物种倾向于起源于热带，然后扩散到更高纬度；(2)热带地区作为哺乳动物物种的博物馆，保存了大陆其他地方已经灭绝的物种；以及(3)全球变冷是大约2000万年前至1000万年前南美洲栖息地变化和哺乳动物进化的主要驱动因素。评估这些假设将使我们能够更好地预测生物多样性在未来可能发生的变化，使自然资源保护者能够就保护生物多样性的最佳战略做出更明智的决定。我们的大部分项目将致力于收集基本数据，使我们能够评估上述假设。尽管南美洲总体上有很好的哺乳动物化石记录，但大多数地区来自新热带以外，大约1500-1000万年前的时间片段没有很好地代表出来。我们将通过在新热带玻利维亚的两个相对较新的化石地点进行实地工作来解决这两个问题：Cerdas和Quebrada Honda。从这些地点收集的化石将被带到玻利维亚的波托西，在那里它们将被清理和管理。然后，这些标本将与来自智利南部和阿根廷的类似年龄但通常未被研究的动物群进行比较。我们将根据对现代和化石种群的新研究，通过详细的比较、系统发育分析、个体牙齿变异评估，修改所有这些地区的哺乳动物。我们建议的研究结果将通过各种媒体广泛传播，包括公开讲座、博物馆展品、我们当地的科学咖啡馆和互联网。玻利维亚和美国的学生将通过参与这项研究的实验室和现场方面获得实践的古生物经验，该项目将支持美国博士生的职业发展。

Reevaluation of Firasian Mammal Faunas from Argentina, Bolivia and ChileDarin Croft, Case Western Reserve UniversityRoughly 80% of South America is in the tropics, the low-latitude area on eitherside of the Equator that includes rain forests, deserts, and a variety of other habitats. This vast area the Neotropics harbors most of South Americas biodiversity, as well as a significant part of the earths biodiversity as a whole. The increasing encroachment of humans into the Neotropics and other factors such as climate change have made this an area of highest conservation priority. But what is the best strategy to preserve this biodiversity not only the present biodiversity, but that of the future? One way to answer this question is to study patterns of ancient biodiversity to better understand factors that affect numbers and types of species in particular places at particular times. Our project will take just such an approach by investigating the evolutionary and biogeographic histories of some of the most important and conspicuous members of Neotropical communities: mammals. In particular, we will address three hypotheses about how the modern mammal communities of South America developed over the past 20 million years: (1) mammal species tend to originate in the tropics and then disperse to higher latitudes; (2) the tropics act as a museum for mammal species by preserving species that have gone extinct elsewhere on the continent; and (3) global cooling was the main driver of habitat change and mammal evolution in South America between about 20 and 10 million years ago. Evaluating these hypotheses will allow us to better predict how biodiversity might change in the future, permitting conservationists to make more educated decisions about the best strategies for preserving biodiversity. Most of our project will be devoted to collecting the primary data that will allow us to evaluate the hypotheses described above. Although South America has a good fossil record of mammals overall, most localities are from outside the Neotropics, and the time slice from about 15-10 million years ago is not well represented. We will address both of these issues through fieldwork at two relatively new fossil localities in Neotropical Bolivia that pertain this time interval: Cerdas and Quebrada Honda. Fossils collected from these sites will be taken to Potosí, Bolivia, where they will be cleaned and curated. The specimens will then be compared with those from similarly-aged but generally unstudied faunas from southern Chile and Argentina. We will revise the mammals from all of these localities through detailed comparisons, phylogenetic analyses, by assessments of individual dental variation based on new studies of modern and fossil populations. The results of our proposed research will be broadly disseminated through a variety of media including public lectures, museum exhibits, our local science café, and the internet. Bolivian and US students will gets hands-on paleontological experience through participation in laboratory and field aspects of this research, and the project will support the career development of a US-based Ph.D. student.