Closing the African Gap-Cretaceous and Paleogene Paleontology in the Rukwa Rift Basin, Southwestern Tanzania

亚赤道非洲的化石记录为检验一系列基本的古地理假说提供了关键。由国家地理学会资助的对坦桑尼亚西南部鲁克瓦裂谷盆地的五次探险(2002-06)揭示了新白垩纪和古近纪陆生脊椎动物的多样性。这些发现增加了关键的新数据，直接与白垩纪-第三纪过渡期间冈德瓦南脊椎动物生物地理的相互竞争的假设有关。这笔赠款召集了一个国际和跨学科的团队来描述盆地白垩纪和古近纪沉积中的新动物群。新的化石将被置于一个严格的系统发育框架中，对鲁克瓦裂谷盆地沉积的彻底地质分析将使人们能够在时间和古环境背景下解释分类群。新的化石发现将被用来检验有关冈德瓦南脊椎动物进化和分布的生物地理假说，并在美国和坦桑尼亚的公共教育中展出。智力优势：油田区域在一个有限的地理区域内包括白垩系-第三系界线的两侧。这突显了该地区在白垩纪至早第三纪地质和生物动力学时期对冈德瓦南脊椎动物起源和分布的古生物地理假说进行检验的重要性。到目前为止，只勘探了盆地内的一小部分沉积矿床。在2004/2005年，勘测发现了两个新的露头区域，其中包含保存完好的化石。根据这项拨款，更大的团队和更长的探险将导致更多的新发现。这笔赠款的主要科学目标是：1)继续在已探明的地点开展工作；2)扩大搜索区域，包括未勘探的裂谷盆地地层；3)对该地区进行完整的盆地分析，划定地层的地层、沉积学和沉积格架，以更好地约束沉积物的年龄；4)对新化石进行详细的解剖学和系统发育研究，并利用这些数据评估关于中生代末和早第三纪脊椎动物演化的相互竞争的生物地理假说。更广泛的影响：该小组将通过以下方式开发坦桑尼亚和美国的学术人力资源：1)在达累斯萨拉姆大学开设短期课程讲座；2)通过与该项目相关的实地、实验室和研究传播活动，将美国学生的培训与坦桑尼亚同行联系起来；3)开发一个巡回展览，突出主要发现以及古生物发现和研究的过程。这次展览将为坦桑尼亚严重缺乏服务的观众加强非正式的科学学习资源，同时为美国学生和教职员工提供一个发展技能的论坛，旨在吸引科学和普通观众。

The fossil record of sub-equatorial Africa holds keys for testing a range of fundamental paleobiogeographic hypotheses. Five expeditions (2002-06) to the Rukwa Rift Basin in southwestern Tanzania funded by the National Geographic Society have revealed a diversity of new Cretaceous and Paleogene terrestrial vertebrates. These discoveries add crucial new data that bear directly on competing hypotheses concerning Gondwanan vertebrate biogeography during the Cretaceous-Tertiary transition. This grant assembles an international and interdisciplinary team to characterize novel faunas from Cretaceous and Paleogene deposits in the basin. New fossils will be placed into a rigorous phylogenetic framework, and thorough geological analysis of Rukwa Rift Basin deposits will allow taxa to be interpreted in both temporal and paleoenvironmental contexts. New fossil discoveries will be used to test biogeographic hypotheses concerning the evolution and distribution of Gondwanan vertebrates and exhibited for public education in both the USA and Tanzania. Intellectual Merit: The field area encompasses both sides of the Cretaceous-Tertiary boundary within a restricted geographic area. This underscores the significance of the region for testing paleobiogeographic hypotheses concerning the origin and distribution of Gondwanan vertebrates during the geologically and biologically dynamic period from the Cretaceous into the early Tertiary. To date, only a fraction of the sedimentary deposits within the basin have been explored. In 2004/5, reconnaissance surveys identified two new outcrop areas that contain well-preserved fossils. The larger crews and longer expeditions under this grant will result in additional new discoveries. The primary scientific goals of this grant are: 1) to continue working proven localities; 2) to expand the search area to include unexplored rift basin strata; 3) to perform a complete basin analysis of the area, delineating the stratigraphic, sedimentologic, and depositional framework of the strata, to better constrain the age of the deposits; and 4) to conduct detailed anatomical and phylogenetic studies of new fossils and use these data to assess competing biogeographic hypotheses concerning the evolution of late Mesozoic and early Tertiary vertebrates. Broader Impact:The team will develop academic human resources in both Tanzania and the United States by: 1) offering short course lectures at the University of Dar es Salaam; 2) linking the training of US students with their Tanzanian peers through field, laboratory, and research dissemination activities related to the project; and 3) developing a traveling exhibit highlighting the major finds and the process of paleontological discovery and research. This exhibit will enhance informal science learning resources for greatly underserved audiences in Tanzania, while giving US students and faculty a forum for developing skills aimed at engaging scientific and general audiences alike.