Collaborative Research: Paleontological Investigation of Early Primate Evolution in Asia

在国家科学基金会的支持下，一个由生物人类学家和古生物学家组成的国际团队将在内蒙古二连盆地探索早期新生代（约6000万至4500万年前）的岩层，寻找灵长类动物进化最早阶段的证据。科学小组的美国成员位于卡内基自然历史博物馆（宾夕法尼亚州匹兹堡）、北伊利诺伊大学（伊利诺伊州迪卡尔布）和美国自然历史博物馆（纽约州纽约）。几种不同的证据，包括化石记录和基于DNA长序列分析的进化关系重建，表明灵长类动物进化的最早阶段可能发生在亚洲。然而，亚洲灵长类动物进化的化石记录仍然参差不齐，这一时期的大多数亚洲灵长类动物都是由非常零碎的解剖遗骸记录下来的。因此，对于这些亚洲化石如何适应灵长类动物进化的家谱，科学界并没有达成共识。更普遍的是，对于灵长类动物进化中的重要事件，如灵长类动物的起源和类人猿（灵长类动物群体，包括现存的猴子、猿和人类）的起源，在何时何地发生，还没有达成共识。二连盆地横跨中国和蒙古之间的现代边界，是亚洲唯一一个具有适当年代地层的沉积盆地，在早期新生代的关键时期发现了灵长类动物化石，灵长类动物和类人猿被认为是在这个时期起源的。野外方法将包括三种古生物勘探模式（地表勘探、采石和筛洗）来定位二连盆地新的灵长类化石。分析方法包括基于解剖特征的进化关系的计算机辅助重建，以及解剖学的高分辨率计算机断层扫描（CT）研究。该小组将与地质学家和古环境重建专家合作，建立二连盆地灵长类动物进化的基本年表。这些数据将允许测试灵长类动物何时何地进化的竞争性模型。这个项目的一个特别有趣的目标是确定灵长类动物穿越阿拉斯加和西伯利亚之间的白令海陆桥的古代事件是否与古代全球变暖事件精确对应。这个项目的科学成果将启发人们对最早的灵长类祖先在何时何地以及如何进化的理解。这将使我们对这些最早的灵长类动物如何从亚洲迁移到邻近的大陆（特别是包括北美）有更多的了解，因为地球的物理环境由于板块构造和气候变化而发生了变化。该项目的更广泛影响包括加强中美学者之间的科学合作，培养本科生和研究生在实地和实验室技术方面的能力，以及多种形式的公共教育推广（包括博物馆展览、电视纪录片、大众出版物和公开讲座）。

With support from the National Science Foundation, an international team of biological anthropologists and paleontologists will explore early Cenozoic (ca. 60-45 million year old) rock strata in the Erlian Basin of Inner Mongolia for evidence of the earliest phases of primate evolution. American members of the scientific team are based at the Carnegie Museum of Natural History (Pittsburgh, PA), Northern Illinois University (DeKalb, IL), and the American Museum of Natural History (New York, NY). Several different lines of evidence, including the fossil record and reconstructions of evolutionary relationships based on analyses of long sequences of DNA, suggest that the earliest phases of primate evolution likely transpired in Asia. However, the fossil record of primate evolution in Asia remains spotty, and most of the Asian primates from this time interval are documented by very fragmentary anatomical remains. As a result, there is no scientific consensus about how these Asian fossils fit on the family tree of primate evolution. More generally, there is no consensus regarding where and when such important events in primate evolution as the origin of primates and the origin of anthropoids (the group of primates that includes living monkeys, apes, and humans) occurred. The Erlian Basin, which straddles the modern border between China and Mongolia, is the only depositional basin in Asia bearing rock strata of the appropriate age to yield fossil primates from the crucial interval of early Cenozoic time when primates and anthropoids are thought to have originated. Field methods will include three modes of paleontological exploration (surface prospecting, quarrying, and screen-washing) to locate new fossil primates in the Erlian Basin. Analytic methods include computer-assisted reconstructions of evolutionary relationships based on anatomical features, as well as high-resolution computed tomographic (CT) studies of anatomy. Working with geologists and experts on paleoenvironmental reconstruction, the team will establish the basic chronology of primate evolution in the Erlian Basin. These data will allow testing of competing models of when and where primates evolved. A particularly interesting goal of this project is to determine whether ancient episodes of primate dispersal across the Bering land bridge between Alaska and Siberia correspond precisely to ancient global warming events. The scientific results from this project will enlighten understanding of where, when, and how earliest primate ancestors evolved. This will result in greater knowledge of how these earliest primates migrated from Asia to adjacent continents (notably including North America) as the physical environment of the planet shifted due to plate tectonics and changing climate. Broader impacts of the project include enhanced scientific cooperation between American and Chinese scholars, training of undergraduate and graduate students in both field and laboratory techniques, and multiple forms of public educational outreach (including museum exhibits, television documentaries, popular publications, and public lectures).