Ecological Change in a Mammalian Community in Extreme Southern Patagonia

生物人类学家、脊椎动物古生物学家和地质学家的这项跨学科研究工作将研究哺乳动物如何适应中新世(2300-530万年前)不断变化的环境。来自中中新世圣克鲁斯组的灵长类和树懒化石得到了非凡的保存，这使得对全球气温高峰前后的饮食、身体大小、运动模式和群落生态的研究成为可能。今天，南美洲的这些群体主要是草食性的，完全居住在树上；他们还容易受到栖息地破坏和气候模式变化的影响，因为他们依赖温暖潮湿的森林。了解这些群体如何适应过去的重大气候变化，将促进更广泛地了解生态变化对脆弱哺乳动物群体的影响。该项目还将促进国际合作，支持研究生培训、公共科学推广和K-12科学推广，包括开发教材包。这个项目的重点是灵长类和树懒生活在全球气温大幅上升(中新世中期气候最佳时期)之前和之后。此前，关于阿根廷圣克鲁斯组的大部分工作都集中在该组(较老的)下段丰富的油田遗址上。这一项目为研究上亚段与最高温度重合的年轻地点提供了机会。以前的生态重建表明，下层的生境更温暖、更潮湿、更封闭的森林，而上层的生境是开阔的林地。然而，对化石遗址的新测年表明，上亚段时期全球气温较高，这让人们对这些早期的生态重建产生了怀疑。该项目将侧重于从已知的上级成员所在地收集新的化石样本，并寻找新的地点。它还将包括新的地质研究，以改善各地之间的相关性，并将包括对植物遗骸的深入分析，以帮助生态重建。成员之间的哺乳动物比较将集中在树懒和灵长类生物学的三个关键方面：体重重建、饮食推断和运动推断。这些方面生物学差异的证据将包括牙齿和长骨的大小和形态。研究人员将使用尖端技术来量化牙齿磨损和地形以及长骨尺寸和横截面特性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This interdisciplinary research effort among biological anthropologists, vertebrate paleontologists, and geologists, will study how mammals adapted to their changing environment during the Miocene epoch (23-5.3 million years ago). The extraordinary preservation of primate and sloth fossils from the Mid-Miocene Santa Cruz Formation allows investigation of diet, body size, locomotor patterns, and community ecology before and after a peak in global temperature. Today, these groups in South America are primarily herbivorous and wholly tree-dwelling; they are also vulnerable to habitat destruction and shifts in weather patterns because they depend on warm, wet forests. Understanding how these groups adapted to major climatic shifts in the past will advance scientific knowledge about the effects of ecological change on vulnerable mammalian groups more generally. The project also will foster international collaborations and support graduate student training, public science outreach, and K-12 science outreach including the development of teaching kits. This project will focus on primates and sloths living before and after a major spike in global temperature (Mid Miocene Climatic Optimum). Previously, most of the work on the Santa Cruz Formation of Argentina has focused on the rich field sites of the (older) Lower Member of the formation. This project provides an opportunity to study the younger sites of the Upper Member, which coincide with the temperature maximum. Previous ecological reconstructions suggested that the habitats of the Lower Member were warmer, wetter, more closed forests and that those of the Upper Member were open woodland. However, new dating of the fossil sites suggests that global temperature was higher during the time of the Upper Member, casting doubt on these earlier ecological reconstructions. This project will focus on gathering new fossil samples from known Upper Member localities and on finding new localities. It will also include new geological research to improve correlations across localities and it will include an in-depth analysis of plant remains to help with ecological reconstruction. Mammalian comparisons between members will focus on three key aspects of sloth and primate biology: body mass reconstruction, dietary inference, and locomotor inference. Evidence for differences in these aspects of biology will consist of the size and morphology of teeth and long bones. Researchers will use cutting-edge techniques to quantify tooth wear and topography as well as long bone dimensions and cross-sectional properties.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.