Can habitat and elevation explain mid-Miocene Neotropical mammal provinciality?

摘要：为什么有这么多物种生活在热带地区？这个问题只能通过揭示地质时期影响物种多样性的因素来回答。对这些因素更好的概念性理解将使政府和保护组织就如何保护现代热带生物多样性做出更明智的决定。该项目将通过绘制玻利维亚一处名为奎布拉达本田（Quebrada Honda）的1300万年前化石遗址的气候和栖息地的详细图片，为这项工作做出贡献。除了产生新的科学见解外，该项目还将产生各种更广泛的影响，包括：增加玻利维亚学生和教师对科学的参与；支持女性博士候选人的职业发展；并通过新的合作加强克利夫兰的研究基础设施。拟议的研究结果将通过英语和西班牙语的各种媒体传播，包括克利夫兰自然历史博物馆永久展品中的多媒体展览模块，以及随附的移动应用程序，说明科学家如何解释过去的气候和栖息地。技术摘要：在南美洲热带地区，已知的哺乳动物化石遗址很少。其中两个遗址是同时期的（中新世中期晚期），地理上相距很远，因此提供了一个独特的机会来检验关于南美洲地理地方性发展的假设。其中一个地点，哥伦比亚的拉文塔，已经被详细研究过。另一个地点，玻利维亚的Quebrada Honda，将是我们实地工作密集型项目的重点，该项目将利用各种地质和古生物学技术产生关于沉积环境和栖息地的新数据。主要目的包括：(1)对各主要化石产地进行地层对比，确定化石聚集的方式和速率；(2)开展古土壤和化石的详细研究，重建古代陆地表面，记录过去的环境；(3)利用哺乳动物的生态特征推断其生活的栖息地。这些数据将产生一幅关于克布拉达本田古代气候和栖息地的全面图景，并将与拉文塔的数据进行比较，以检验这两个地点哺乳动物动物群的巨大差异是否可以用古环境的差异来解释。这些观测结果还将用于验证最近基于块状同位素的断言，即化石沉积时，Quebrada Honda的海拔高度超过2公里。

Non-technical Abstract:Why do so many species live in the tropics? This question can only be answered by uncovering the factors that have affected species diversity over geologic time. A better conceptual understanding of these factors will enable government and conservation organizations to make more informed decisions about how to preserve modern tropical biodiversity. The project will contribute to this effort by generating a detailed picture of the climate and habitats of a 13 million-year-old fossil site in Bolivia known as Quebrada Honda. In addition to producing new scientific insights, the project will have a variety of broader impacts including: increasing participation of Bolivian students and faculty in the sciences; supporting career development of a female PhD candidate; and enhancing Cleveland research infrastructure through new collaborations. Results of the proposed research will be disseminated through a variety of media in English and Spanish including a multimedia exhibit module in the permanent exhibits of the Cleveland Museum of Natural History and an accompanying mobile app on how scientists interpret past climates and habitats.Technical Abstract:Few well-sampled fossil mammal sites are known from the South American tropics. Two of these sites are contemporaneous (late middle Miocene) and widely separated geographically and thus present a unique opportunity to test hypotheses about the de-velopment of South American geographic provinciality. One of these sites, La Venta, Colombia, has been studied in detail. The other site, Quebrada Honda, Bolivia, will be the focus of our fieldwork-intensive project, which will generate new data about deposi-tional environments and habitats of using a variety of geological and paleontological techniques. The main objectives include: (1) stratigraphically correlating the main fossil-producing areas at Quebrada Honda with one another to determine the manner and rate by which fossils accumulated; (2) undertaking detailed studies of ancient soils and trace fossils to reconstruct ancient land surfaces and document past environments; and (3) using ecological characteristics of mammals to deduce the habitats in which they lived. These data will produce a comprehensive picture of the ancient climate and habitats of Quebrada Honda and will be compared to data from La Venta to test whether the great differences in the mammal faunas of these two sites can be explained by differences in paleoenvironment. The observations will also be used test the recent clumped isotope-based assertion that the elevation of Quebrada Honda was more than 2 km when the fossils were deposited.