Fossil Reptiles from the Late Cretaceous (Campanian-Maestrichtian) of Vega Island, 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，支持对南极半岛地区织女岛恐龙和海洋爬行动物化石的古生物研究。1997-98年南半球夏季野外考察期间，在南极半岛的织女岛晚白垩世沉积中发现了大量脊椎动物和无脊椎动物化石。这些化石代表了晚白垩世动物群的广泛多样性。不仅发现了南极洲的第一只鸭嘴龙恐龙，还发现了几种海洋爬行动物(蛇颈龙和马赛龙)的标本，其中许多都被发现了。到目前为止，海洋爬行动物在南极洲鲜为人知，只有一个物种被描述过。该奖项支持关于织女岛洛佩兹-贝尔托达诺组古动物群的爬行动物部分的准备、保护和研究。爬行动物化石标本，包括大量幼体，是在织女岛上对晚白垩世哺乳动物进行实地研究时的意外发现(见美国国家科学基金会授予M.O.伍德伯恩的OPP-9615236和授予J.A.凯斯的OPP-9615933)。至少发现了两种不同的马赛龙，两种蛇颈龙，以及鸭嘴龙恐龙的第一个证据。鸭嘴龙表明，至少在最新的马斯特里赫特时期(马斯特里赫特时期涵盖了大约7400万到6600万年前)的一条扩散路线，为陆地生物从北美通过南美洲到至少南极洲的扩散提供了途径，并有助于假设的前往澳大利亚的路线。海洋爬行动物还展示了以前未被承认的古地理关系，对这些关系的追求构成了本奖项下继续进行野外工作的基础。至少有一个镶嵌龙分类群似乎在冈瓦那存在的时间更长，而另一个可能与北方的分类群有更密切的亲缘关系。南极洲的蛇颈龙似乎也残留地分布在冈德瓦南大陆，因为大多数北方近亲到白垩纪已经灭绝。在这一点上，这些古地理关系是有效的假说，必须通过回收更多的标本和研究冈德瓦南海洋爬行动物的历史和分布来检验。由于南极洲在晚白垩世处于冈瓦那的中心位置，对其进行研究对于了解海洋爬行动物的分布至关重要。该奖项支持现有收藏的进一步工作以及新的实地工作，以找回上个野外季节发现的恐龙和海洋爬行动物化石。

This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports paleontological research on dinosaur and marine reptile fossils from Vega Island in the Antarctic Peninsula region. Field work during the 1997-98 austral summer field season yielded substantial numbers vertebrate and invertebrate fossils from the late Cretaceous deposits of Vega Island on the Antarctic Peninsula. The fossils represent a wide diversity of Late Cretaceous fauna. Not only was the first hadrosaur dinosaur from Antarctica discovered, but several specimens of marine reptiles (plesiosaurs and mosasaurs) were found and many were recovered. Heretofore, marine reptiles had been poorly known from Antarctica, with only one species having been described. This award supports the preparation, conservation, and research concerning the reptilian portion of the paleofaunal assemblages of the Lopez de Bertodano Formation on Vega Island.The fossil reptile specimens, including numerous juveniles, were an unexpected discovery during field research on late Cretaceous mammals on Vega Island (see NSF awards OPP-9615236 to M. O. Woodburne and OPP-9615933 to J. A. Case). At least two different mosasaurs were found, two plesiosaurs, and the first evidence of a hadrosaurian dinosaur. The hadrosaur indicates that a dispersal route at least by the latest Maastrichtian (the Maastrichtian encompasses the period from about 74 to 66 million years ago) provided an avenue for dispersal of terrestrial creatures from North America through South America to at least Antarctica, and aids in the postulated route to Australia. The marine reptiles also demonstrate previously unrecognized paleogeographic relationships, and the pursuit of these relationships forms the basis for continued field work under this award. At least one mosasaur taxon appears to persist longer in Gondwana, whereas the other may have closer affinities with northern taxa. The plesiosaurs from Antarctica also appear to have relict distribution among the Gondwanan continents, as most northern relatives are extinct by the Cretaceous. At this point, these paleogeographic relationships are working hypotheses which must be tested by the recovery of additional specimens and by study of the history and distribution of Gondwanan marine reptiles. Because of Antarctica's position at the center of Gondwana during the Late Cretaceous, its study is crucial to the understanding of the distribution of marine reptiles. This awards supports further work on the existing collections as well as new field work for recovery of the dinosaur and marine reptile fossils located last field season.