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

0087972马丁该奖项由极地项目办公室南极地质和地球物理项目提供，支持加州的圣玛丽学院、南达科他州矿业与技术学院和阿根廷南极研究所（Instituto Antartico Antarctino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。坎帕尼亚期至马斯特里赫特期（距今8000万年至6500万年前）是关于脊椎动物地理学（即由于移动的陆地而导致的扩散和分离）以及南极洲和其他南半球大陆（包括印度，即冈瓦纳）之间的进化的重要时间间隔。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及更远地区（如澳大利亚）的扩散，以及现代鸟类从南极向北的扩散，都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上的脊椎动物，也包括海洋环境中的脊椎动物。南极洲的海洋爬行动物分布广泛，但也有局限性。南极洲半岛和巴塔哥尼亚是韦德尔古生物地理省的最西部，该地区从巴塔哥尼亚经南极洲半岛和南极洲西部延伸至澳大利亚和新西兰。在这个省内，分布着南美洲与马达加斯加和印度，以及澳大利亚之间脊椎动物交流的传播路线。根据主要研究者先前的研究结果，假设南美洲北方和南极克拉通之间的地峡曾在白垩纪晚期将典型的北美恐龙，如鸭嘴龙（鸭嘴龙）和可能的有袋类动物带到南极洲，而海洋爬行动物则沿着沿海沃茨游泳。最后，这一地区是现代鸟类进化的摇篮，如果不是起源的话，也是一套典型的南半球植物进化的摇篮。为了证实和扩展这些假设，必须继续对南极半岛詹姆斯罗斯盆地最新白垩纪沉积物进行调查。沿着南极半岛东部詹姆斯罗斯盆地洛佩斯德贝尔托达诺组的兰姆角和桑威奇海崖地质单元显示出海洋和陆地沉积的混合物。在过去的野外考察季节中，从这些沉积物中发现了以下脊椎动物：蛇颈龙和沧龙类海洋爬行动物;食草恐龙;食肉恐龙;以及各种现代鸟类，包括滨鸟、涉禽和泻湖鸟。本项目将进行新的野外考察，以发现新的标本，以测试有关冈瓦纳晚白垩世脊椎动物的地理和进化假设。计划于2002年1月和2003年对维加岛的兰姆角、桑威奇海崖和福尔斯岛角的东坡以及詹姆斯罗斯岛的玛尔塔湾地区进行实地考察，这项研究将对几种脊椎动物的进化和地理分布产生重要的新认识。这是一个与来自宇航科学院的阿根廷科学家合作的研究项目，它继续了1995年开始的富有成效的合作。此外，我们将继续与来自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的各自机构开展合作。

0087972MartinThis 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.