Early Hominin Adaptation in the Southern East African Rift

超过150年的人类研究仍然留下了一些关于我们早期祖先进化的基本问题。人类和鲍氏傍人谱系早期阶段的觅食策略、它们对气候变化的适应以及与主要草地和林地边界附近的相关古生态学等研究课题尚未得到研究。基于稳定同位素的东非人属和鲍氏傍人饮食的研究主要限于东非裂谷（东非裂谷）东分支的化石证据，主要是图尔卡纳盆地。在2 Ma，两组不同的觅食策略，同时存在：P.鲍氏消耗C4为主的饮食，而人消耗了更高比例的C3资源。这些结果是同时向越来越开放的C4草原在一个持续炎热的环境，最终发展成为现代草原为主的索马里-马赛特有区的生物群落转变。由于当时发现的化石极其罕见，因此缺乏限制人类和P. boisei在早期进化阶段饮食抵消的起源，时间和进化的数据（2 Ma以前）。与东支分支不同，本项目关注的是位于东支南部的两个人类遗址，该地区基本上未被充分勘探：（1）上新世-更新世Chiwondo/Chitimwe层（Karonga盆地，马拉维北部），在今天树木繁茂的赞比西亚稀树草原上，这里是唯一一个包含H. rudolfensis和P. boisei化石;（2）更新世H.直立人产生马尼亚拉床（马尼亚拉盆地，坦桑尼亚北部），位于今天的C4草为主的索马里-马赛特有区的主要稀树草原边界以北。该项目将受益于优秀的设施，以研究早期人类的适应：除了成熟的d13 C，d18 O和dD同位素技术外，还采用了新的成团同位素地球化学和土壤碳酸盐U-Pb测年方法。分配独家Senckenberg收集材料，其中包括最早的人属化石，以及使用马拉维湖ICDP钻芯材料和在该领域新收集的样品，是一个独特的附加值。该项目涉及三个工作包：一）来自非洲南部的早期鲁道夫人和鲍氏傍人的饮食，二）东南非洲稀树草原生态系统的上新世-更新世古温度，和三）马尼亚拉盆地的上新世-更新世古植被。通过对土壤碳酸盐的U-Pb测年，将为上新世-更新世Karonga盆地化石沉积物提供第一个绝对年龄。

Over 150 years of extensive hominin research still leaves several fundamental questions about the evolution of our early ancestors. Research subjects such as foraging strategies of early stages of the lineages of Homo sp. and Paranthropus boisei, their adaptation to climate change, as well as the associated paleoecology close to major grass- and woodland boundaries have not yet been examined. Stable-isotope based research of East African Homo sp. and Paranthropus boisei diet is mainly limited to fossil evidence from the Eastern Branch of the East African Rift (EAR), mainly the Turkana Basin. At 2 Ma, two groups with distinct foraging strategies were simultaneously present: P. boisei consumed a C4 dominated diet, whereas Homo consumed a higher fraction of C3 resources. These results are concurrent with a biome shift towards increasingly open C4 grasslands in a continuously hot environment, which ultimately developed into the modern grassland-dominated Somali-Masai Endemic Zone. Data that constrain the origin, timing and evolution of the dietary offset of Homo and P. boisei during their early evolutionary stages are lacking, due to extremely rare fossil discoveries of that time (prior 2 Ma).In contrast to the Eastern Branch of the EAR, this project focuses on two hominin sites in the largely underexplored southern part of the EAR: (1) the Plio-Pleistocene Chiwondo/Chitimwe Beds (Karonga Basin, N Malawi), which host the only early hominin locality in today's wooded Zambezian Savanna that comprise H. rudolfensis and P. boisei fossils, and (2) the Pleistocene H. erectus yielding Manyara Beds (Manyara Basin, N Tanzania), located just north of a major savanna boundary in today's C4 grass-dominated Somali-Masai Endemic Zone. The project stands to benefit from excellent facilities in order to study early hominin adaptation: novel methods of clumped isotope geochemistry and U-Pb dating of soil carbonates in addition to the well-established d13C, d18O and dD isotope techniques. The allocation of exclusive Senckenberg collection material, which includes on of the earliest fossils of the genera Homo, as well as the use of Lake Malawi ICDP drill core materials and newly collected samples in the field, is a unique added value. This project addresses three work packages: I) Diet of early Homo rudolfensis and Paranthropus boisei from the southern part of the EAR, II) Plio-Pleistocene paleotemperatures of Southeast African savanna ecosystems, and III) Plio-Pleistocene paleovegetation of the Manyara Basin. These lead to the overarching synthesis of comparing Plio-Pleistocene African paleotemperatures, ecosystem patterns and early hominin diet across a woodland-grassland savanna boundary.The necessary geochronological framework will be obtained through U-Pb dating of soil carbonate, which will provide the first absolute ages for the poorly dated Plio-Pleistocene Karonga Basin fossil bearing deposits.