Collaborative Research: Climatic and Biotic Transformations of Neogene Mammalian Faunas of Pakistan

合作研究：巴基斯坦新近纪哺乳动物群的气候和生物转变——Catherine Badgley，密歇根大学安阿伯分校，MIThure Cerling，犹他大学盐湖城分校，David Pilbeam，哈佛大学剑桥分校。来自四个机构的合作者将讨论巴基斯坦中新世化石记录中哺乳动物对全球气候、海平面、构造障碍和移民物种变化的生态和进化反应。Siwalik记录由高度化石化的新近纪沉积物组成，沉积在喜马拉雅前陆盆地，从巴基斯坦到缅甸。在巴基斯坦的波特瓦尔高原，这一记录提供了一个无与伦比的动物和环境变化的历史，在过去1800万年的连续地层序列中。在这一时期，哺乳动物古群落呈现出世界性群体、地方性谱系和遗存分类群的混合变化。从深海岩心和其他地质证据可以得知，环境过程可能驱动了这些动物变化。这些过程发生在不同的生物地理尺度上，从全球气候系统和海平面到区域（南亚）构造运动，再到当地洪盆及其植被和当地气候。本文将通过(1)评估1800万至550万年前不同地球动力和气候条件下的哺乳动物区系变化，以及(2)整合Siwalik记录中关于古气候变化的多种指标，包括利用氧化铁估算土壤湿度的新地球化学方法、蜗牛表皮降水季节性信息，以及其他研究方法，来验证环境过程与生物响应之间的关系。牙釉质和土壤碳酸盐的稳定同位素，以及使用功能形态学测量已灭绝哺乳动物的饮食和体型。

Collaborative Research: Climatic and Biotic Transformations of Neogene Mammalian Faunas of Pakistan - Catherine Badgley, University of Michigan, Ann Arbor, MIThure Cerling, University of Utah, Salt Lake City, UT, David Pilbeam, Harvard University, Cambridge, MAAbstractCollaborators from four institutions will address the ecological and evolutionary responses of mammals from the Miocene fossil record of Pakistan to changes in global climate, sea level, tectonic barriers, and immigrant species. The Siwalik record consists of highly fossiliferous Neogene sediments deposited in the Himalayan foreland basin from Pakistan to Myanmar. In the Potwar Plateau of Pakistan, this record provides an unparalleled history of faunal and environmental change in a continuous sequence of strata spanning the last 18 million years. During this time period, mammalian paleocommunities exhibited a changing mixture of cosmopolitan groups, endemic lineages, and relict taxa. Environmental processes that may have driven these faunal changes are known from deep-sea cores and other geological evidence. These processes occurred at different biogeographic scales, ranging from those of the global climate system and sea level to regional (South Asian) tectonism to the local floodbasin and its vegetation and local climate. The proposed analyses will test the relationship between environmental processes and biological responses by (1) evaluating mammalian faunal change under different geodynamic and climatic conditions over the interval between 18.0 and 5.5 million years ago, and (2) integrating multiple indicators of changing paleoclimate from the Siwalik record, including a new geochemical method for estimating soil moisture using iron oxides, information from snail opercula about seasonality of precipitation, stable isotopes from tooth enamel and soil carbonate, and measures of diet and body size for extinct mammals using functional morphology.