COLLABORATIVE RESEARCH: Evolution and Biogeography of Late Cretaceous Vertebrates from the James Ross Basin, Antarctic Peninsula

该奖项由极地方案办公室南极地质和地球物理方案提供，支持加州圣玛丽学院、南达科他州矿业与技术学院和阿根廷南极研究所(Instituto南极洲阿根廷研究所或IAA)之间的合作研究项目，以调查南极半岛地区詹姆斯罗斯盆地的晚中生代脊椎动物古生物学。寒武纪到马斯特里赫特时代(8000万至6500万年前)是脊椎动物生物地理学(即由于陆块移动而分散和分离)和南极洲与其他南半球大陆(包括印度，即冈瓦那)之间的演化的重要时间间隔。此外，陆生脊椎动物(即恐龙和有袋类哺乳动物)从北美经巴塔哥尼亚和南极半岛向南极洲和更远的地方(如澳大利亚)的扩散，以及现代鸟类从南极洲向北的扩散，是古生物学中尚未解决的重要问题。这些扩散事件不仅包括陆地领域的脊椎动物，也包括海洋环境中的脊椎动物。在南极洲发现了广泛分布和本地化的海洋爬行动物物种，这引发了关于它们与陆地动物一起扩散的问题。南极半岛和巴塔哥尼亚是韦德利安古生物地理省最西部的部分，该地区从巴塔哥尼亚穿过南极半岛和南极洲西部延伸到澳大利亚和新西兰。在这个省，脊椎动物在南美洲和：1)马达加斯加和印度，以及2)澳大利亚之间有相互交流的传播路线。根据主要研究人员之前的工作，推测南美洲北部和南极克拉通之间的地峡将典型的北美恐龙，如鸭嘴龙(鸭嘴龙)和可能的有袋类动物带到了南极洲，而海洋爬行动物则在最近的白垩纪沿着沿海水域游泳。最后，该地区是现代鸟类群体进化的摇篮，也是一系列典型南半球植物进化的摇篮。为了证实和扩大这些假说，必须继续对南极半岛詹姆斯罗斯盆地最新的白垩纪沉积进行调查。南极半岛东部詹姆斯·罗斯盆地洛佩兹·德·贝尔托达诺组的兰姆角和桑威奇断崖地质单元，展示了海相和陆相沉积的混合。在过去的野外季节，从这些沉积沉积物中发现了下列脊椎动物：蛇颈龙和马萨龙海洋爬行动物；植物食肉恐龙；食肉恐龙；以及各种现代鸟类，包括滨鸟、涉禽和泻湖鸟。该项目将进行新的野外工作，以恢复新的标本，以检验冈瓦那晚白垩世脊椎动物的生物地理和进化假说。实地考察工作计划于2002年1月和2003年1月进行，以探索维加岛上的兰姆角、三明治峭壁和法夫岛点的东坡，以及詹姆斯罗斯岛的圣玛尔塔湾地区。这项研究将对几种脊椎动物物种的进化和地理分布产生重要的新见解。这一结果对于理解地球上生命的发展和进化非常重要。这是一个与国际天文学协会的阿根廷科学家合作的研究项目，它延续了始于1995年的富有成效的合作。此外，将继续与拉普拉塔博物馆的脊椎动物古生物学家在实地以及我们在阿根廷和美国各自机构的合作。

0003844CaseThis award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a collaborative research project between the Saint Mary's College of California, the South Dakota School of Mines and technology, and the Argentine Antarctic Institute (Instituto Antartico Argentino or IAA) to investigate the Late Mesozoic vertebrate paleontology of the James Ross Basin in the Antarctic Peninsula region. The Campanian through the Maastrichtian ages (80 to 65 million years ago) is an important time interval concerning vertebrate biogeography (i.e. dispersals and separations due to moving landmasses) and evolution between Antarctica and other Southern Hemisphere continents (including India, i.e. Gondwana). Moreover, the dispersal of terrestrial vertebrates (i.e. dinosaurs and marsupial mammals) from North America to Antarctica and beyond (e.g. Australia) via Patagonia and the Antarctic Peninsula, as well as the dispersal of modern birds from Antarctica northward are important unresolved questions in paleontology. These dispersal events include vertebrates not only in the terrestrial realms, but also in marine settings. Both widely distributed and localized marine reptile species have been identified in Antarctica, creating questions concerning their dispersal in conjunction with the terrestrial animals.The Antarctic Peninsula and Patagonia represent the western-most portion of the Weddellian Paleobiogeographic Province, a region that extends from Patagonia through the Antarctic Peninsula and western Antarctica to Australia and New Zealand. Within this province lie the dispersal routes for interchanges of vertebrates between South America and: 1) Madagascar and India, and 2) Australia. As the result of previous work by the principal investigators, it is postulated that an isthmus between more northern South America and the Antarctic craton has served to bring typical North American dinosaurs, such as hadrosaurs (duck-billed dinosaurs) and presumably marsupials traveling overland, while marine reptiles swam along coastal waters, to Antarctica in the latest Cretaceous. Finally, this region has served as the cradle for the evolution, if not the origin, for groups of modern birds, and evolution of a suite of typical southern hemisphere plants.In order to confirm and expand upon these hypotheses, investigations into the latest Cretaceous deposits of the James Ross Basin, Antarctica Peninsula must be continued. The Cape Lamb and Sandwich Bluff geological units, of the Lopez de Bertodano Formation in the James Ross Basin along the eastern Antarctic Peninsula, exhibit a mixture of marine and terrestrial deposits. The following vertebrates have been recovered from these sedimentary deposits during previous field seasons: plesiosaur and mosasaur marine reptiles; plant eating dinosaurs; a meat eating dinosaur; and a variety of modern bird groups, including shorebirds, wading birds and lagoonal birds.This project will undertake new fieldwork to recover new specimens in order to test biogeographic and evolutionary hypotheses concerning Late Cretaceous vertebrates in Gondwana. Fieldwork is planned in January 2002 and 2003 to explore the eastern slopes of Cape Lamb, Sandwich Bluff and False Island Point on Vega Island, and the Santa Marta Cove area of James Ross Island.This research will result in important new insights about the evolution and geographic dispersal of several vertebrate species. The results are important to understanding the development and evolution of life on Earth.This is a collaborative research project with Argentinean scientists from the IAA and it continues a productive collaboration that began in 1995. In addition, collaboration with vertebrate paleontologists from the Museo de La Plata, both in the field and at our respective institutions in Argentina and in the United States, will continue.