The Crazy Mountains Basin Project: Composition, Diversity, and Evolution of Paleocene Mammalian Faunas

疯狂山脉盆地项目：古新世哺乳动物动物群的组成、多样性和进化大卫·克劳斯(石溪大学)乔纳森·布洛赫(南达科他州矿业与技术学院)(EAR-0308902)摘要随着非鸟类恐龙的灭绝，古新世(大约6500万至5500万年前)是现代哺乳动物进化史上关键的形成时期。哺乳动物动物群组成在古新世的更替，特别是在托雷约期(TO)和蒂凡尼期(Ti)北美陆地哺乳动物时代之间，在新生代，也就是所谓的哺乳动物时代，是最显著的。就在那时，哺乳动物经历了迅速的多样化，成为占主导地位的陆地动物。古新世哺乳动物动物群更替的原因和机制被不同地归因于气候变化或假灭绝，但到目前为止，检验这些假说所需的数据一直很匮乏。这项提案试图通过使用大量的化石样本来记录TO/Ti哺乳动物的动物群周转模式，这些化石样本是石溪大学野外工作人员于20世纪80年代和90年代初从蒙大拿州东部疯狂山脉盆地(CMB)收集的。在这里提出的岩石、磁学和生物地层学分析的背景下进行研究时，这些地区的样品将提供对修订古新世生物年代学至关重要的数据。拟议的项目还将导致开发和实现盆地西侧一个鲜为人知和采样不足的地点--邦塔尔地区的巨大潜力。来自班塔尔的石灰岩已经开始出土一些最完整、保存最完好的哺乳动物头骨和骨骼，这些头骨和骨骼是古新世已知的。来自CMB东西两侧的样本将显著增加对古新世哺乳动物的系统发育、功能形态和古生态学的了解。对这些样品的鉴定、描述和分析，结合基于古植物群和哺乳动物牙齿稳定同位素分析的新的古气候数据，将被用来解决关于古新世动物群快速更替的机制和原因的长期悬而未决和越来越有争议的问题。

The Crazy Mountains Basin Project: Composition, Diversity, and Evolution of Paleocene Mammalian FaunasDavid Krause (Stony Brook University)Jonathan Bloch (South Dakota School of Mines & Technology)(EAR-0308902)ABSTRACTWith the extinction of non-avian dinosaurs, the Paleocene epoch (roughly 65 to 55 million years ago) was a critically formative interval in the evolutionary history of modern mammals. Turnover in the composition of the mammalian fauna during the Paleocene, and particularly between the Torrejonian (To) and Tiffanian (Ti) North American Land Mammal Ages, was among the most significant during the Cenozoic, the so-called Age of Mammals. It is then that mammals underwent rapid diversification and became dominant land animals. The causes and mechanisms of Paleocene mammalian faunal turnover have been variously ascribed to either climatic change or pseudo-extinction but the data required to test these hypotheses have, heretofore, been wanting. This proposal seeks to document the pattern of To/Ti mammalian faunal turnover by employing massive samples of largely undescribed fossils, collected by Stony Brook University field crews in the 1980s and early 1990s from the eastern Crazy Mountains Basin (CMB), Montana. When studied in the context of the careful litho-, magneto- and biostratigraphic analyses proposed here, the samples from these localities will provide data crucial for a revision of the biochronology of the Paleocene epoch. The proposed project will also result in exploitation and realization of the vast potential of a poorly known and under-sampled site, the Bangtail locality, on the western side of the basin. Limestones from Bangtail have begun to yield some of the most complete and exquisitely preserved mammalian skulls and skeletons yet known for the Paleocene. The samples from both the eastern and western sides of the CMB will significantly augment knowledge of the phylogeny, functional morphology, and paleoecology of Paleocene mammals. Identification, description, and analysis of these samples, coupled with new paleoclimatic data based on paleofloras and stable isotope analyses of mammalian teeth, will be employed to address long unanswered and increasingly controversial questions concerning the mechanisms and causes of rapid faunal turnover during the Paleocene.