Doctoral Dissertation Improvement: Paleoecological Modeling and the Evolution of Early Eocene Primates in the Bighorn Basin, WY

博士论文改进：怀俄明州比格霍恩盆地的古生态模型和早期始新世灵长类动物的进化

• 批准号: 0303768
• 负责人: Kenneth Rose
• 金额: $ 0.84万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-15 至 2004-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0303768&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Improvement; Paleoecological; Modeling

This study is proposed to advance the current understanding of the origin and evolution of the earliest primates. A broad-based, multidisciplinary approach will be used to analyze one of the most complete sequences of early fossil primates known. Though important contributions will also be made to the sciences of paleontology and paleoecology (the study of the interactions of ancient ecosystems), the main goal of this project is to relate primate evolution to environmental and community changes. The Willwood Formation of the Bighorn Basin, Wyoming, contains an extraordinary record of the history of early modern mammals. Deposited between 55 and 52.5 million years ago, it is one of the richest and most continuous early Eocene sequences in the world. Primates formed a significant and diverse element of the fauna preserved in the Willwood Formation, accounting for 10-20% of the individuals from many Willwood assemblages. Most of the fossil localities from the southern part of the Bighorn Basin have been tied into a composite sedimentary section of nearly 700m in thickness that is exposed over an area of more than 3000 km2.Intense fossil collecting efforts have been focused in the southern Bighorn Basin since the early 1960s, resulting in an enormous collection of fossils conservatively estimated to include as many as 100,000 vertebrate specimens. Recently, paleoenvironmental studies of the Bighorn Basin have incorporated innovations in stable isotope analysis to characterize the climate and depositional environment of these sediments. These new data are in excellent accord with previous paleoenvironmental reconstructions based on fossil soils and plant leaf physiognomy. With the emergence of these exciting and varied lines of evidence, it is now possible to examine the evolution of the Willwood primates in a tightly constrained time frame and in the context of a changing, regional environment.Studies of this type, grouped loosely under the heading 'paleoecology', have been critical in shaping hypotheses of primate and hominid evolution. The proposed project aims to accomplish a paleoecological analysis of the southern Bighorn Basin mammal community in two stages. The first is to quantify, using a random-sampling procedure, the pattern of faunal evolution during the first 2.5 million years of the Eocene in the southern Bighorn Basin. Preliminary analysis suggests that there have been episodes of concentrated faunal change (turnover). In the second stage, the resultant pattern will be tested for correspondence with the predictions of eight different current hypotheses of ecological models for evolutionary change. The results of this study will have important implications for scenarios of the evolution of the earliest primates and current arguments surrounding the paleoecological modeling of ancient ecosystems.The broader impacts of this study will include a contribution to current debates surrounding the impact of climate change on modern mammalian ecosystems. The results will illustrate the behavior and evolution of an ancient ecosystem in the face of changing regional temperature and moisture regimes, and shifting geological environments. In addition, the broader impacts include the graduate training of the Co-PI. The data collected will be useful in further research and will advance the scientific career of the Co-PI.

这项研究旨在增进目前对最早灵长类动物起源和进化的理解。将采用基础广泛、多学科的方法来分析已知最完整的早期灵长类化石序列之一。尽管也将对古生物学和古生态学（古代生态系统相互作用的研究）做出重要贡献，但该项目的主要目标是将灵长类动物的进化与环境和群落变化联系起来。 怀俄明州比格霍恩盆地的威尔伍德地层包含了早期现代哺乳动物历史的非凡记录。它沉积于 55 至 5250 万年前，是世界上始新世最丰富、最连续的地层序列之一。灵长类动物是威尔伍德组群中保存的动物群中重要且多样化的组成部分，占许多威尔伍德组合中个体的 10-20%。 Bighorn 盆地南部的大部分化石产地都被连接成一个厚度近 700m 的复合沉积剖面，暴露面积超过 3000 km2。大量的化石收集工作集中在 Bighorn 盆地南部自 20 世纪 60 年代初以来，已收集了大量化石，保守估计包括多达 100,000 个脊椎动物标本。最近，比格霍恩盆地的古环境研究纳入了稳定同位素分析的创新，以描述这些沉积物的气候和沉积环境。这些新数据与之前基于化石土壤和植物叶子面貌的古环境重建非常一致。随着这些令人兴奋和多样化的证据的出现，现在可以在严格限制的时间范围内和不断变化的区域环境的背景下研究威尔伍德灵长类动物的进化。这种类型的研究，松散地分组在“古生态学”标题对于灵长类动物和原始人类进化假说的形成至关重要。该项目旨在分两个阶段完成对大角盆地南部哺乳动物群落的古生态分析。第一个是使用随机抽样程序量化比格霍恩盆地南部始新世前 250 万年的动物群进化模式。初步分析表明，曾出现过集中的动物区系变化（更替）。 在第二阶段，将测试所得模式是否与当前八种不同的进化变化生态模型假设的预测相符。这项研究的结果将对最早的灵长类动物的进化情景以及当前围绕古代生态系统的古生态模型的争论产生重要影响。这项研究的更广泛影响将包括为当前围绕气候变化对现代的影响的争论做出贡献哺乳动物生态系统。研究结果将说明古代生态系统在区域温度和湿度变化以及地质环境变化时的行为和演化。此外，更广泛的影响包括联合首席研究员的研究生培训。收集的数据将有助于进一步的研究，并将促进联合首席研究员的科学事业。