Cretaceous Vertebrates from Madagascar: A Window into the Biogeographic and Plate Tectonic History of Gondwana

马达加斯加的白垩纪脊椎动物：了解冈瓦纳生物地理和板块构造历史的窗口

• 批准号: 1528273
• 负责人: David Krause
• 金额: $ 27万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2016-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1528273&HistoricalAwards=false
• 关键词: Cretaceous; Vertebrates; Madagascar; Window; into

Cretaceous Vertebrates from Madagascar: A Window into the Biogeographic and Plate Tectonic History of GondwanaDavid Krause, Stoneybrook, EAR-1528273Patrick O'Conner, Ohio University, EAR-1525915This proposal is jointly funded by the Sedimentary Geology and Paleobiology Program (EAR/GEO) and the Africa, Near East & South Asia Program/Office of International Science and Engineering (OD). ABSTRACTNon-technical ExplanationThe latter half of the Mesozoic Era witnessed profound changes in the configuration of landmasses that comprised the southern supercontinent Gondwana, with dramatic consequences for the associated vertebrate faunas. Madagascar lay near the center of Gondwana as it fragmented into its component parts. This proposal seeks to continue a project designed to discover and describe vertebrate fossils in a sequence of Cretaceous strata on the island, to analyze their paleobiology, to place them in phylogenetic and geologic context, and to employ them in testing biogeographic and plate tectonic hypotheses related to Gondwana as a whole and Madagascar in particular. PIs work in the Cretaceous of Madagascar is only at the very beginning of reaching its potential. To date, they have quintupled the previously known species diversity of Late Cretaceous vertebrates from the island and have discovered some of the most complete and spectacularly preserved specimens of Late Cretaceous vertebrates from the southern hemisphere and, indeed, the world. Many new taxa have been named and described. But much remains to be done in the vast expanses of paleontologically and geologically unexplored Cretaceous rocks of Madagascar. Many taxa are known by only fragmentary remains; many others are still to be discovered. With continued work, PIs are confident that Madagascar's Cretaceous vertebrate fauna will become one of the best known and best contextualized from the southern hemisphere and one of the primary standards against which other Gondwanan faunas of Cretaceous age are compared.Technical DescriptionPIs propose to continue collecting terrestrial and freshwater vertebrate fossils of latest Cretaceous age from the Berivotra Study Area of the Mahajanga Basin of northwestern Madagascar, which continues to produce exquisite material of poorly known taxa and specimens of new taxa. Although they have published many detailed anatomical, functional, and phylogenetic analyses of taxa known from this basin, many more have been initiated and remain to be completed (in particular, on albuloid and amiid fishes, crocodyliforms, pterosaurs, sauropod and abelisauroid theropod dinosaurs, birds and other paravian theropods, and mammals). Some of this work will entail histological sampling, thus enabling a comparative analysis of ecosystem-scale, inter-element histological variation within single vertebrate skeletons and testing of hypotheses related to possible responses and growth history adaptations of taxa that are phylogenetically constrained, but which exhibit a wide array of morphological and functional specializations. PIs also propose to continue developing newly discovered field areas in the Mahajanga Basin, which are yielding new taxa of roughly the same age but from different paleoenvironmental settings. Finally, they propose to expand their efforts into the Morondava Basin of western Madagascar, where brief expeditions in 2010 and 2012 yielded important finds and demonstrated the potential for many more from strata older than those yielding fossils in the Mahajanga Basin. Discoveries from these earlier horizons will provide a deeper temporal context with which to address biogeographic and plate tectonic hypotheses. Indeed, PIs discoveries continue to have profound implications for the biogeographic history of the extant and extinct Malagasy fauna and for the relative importance of dispersal and vicariance during Gondwanan fragmentation. One of their overarching goals is to provide a key building block for reconstructing Gondwanan biogeographic history in the form of a temporally controlled, well-sampled vertebrate fauna from the Cretaceous of Madagascar analyzed in a rigorous phylogenetic framework, and within the context of accurate paleogeographic reconstructions. It remains a priority to conduct detailed stratigraphic, sedimentologic, and taphonomic studies of all sampled horizons in order to provide temporal control as well as paleoenvironmental and paleoclimatic context. More specifically, PIs propose to conduct: (1) a comprehensive analysis of Maevarano Formation taphonomy that will provide taxonomic summaries and maps for each major quarry, and will detail the preservation of the Maevarano Formation?s exceptionally-preserved vertebrate record; (2) a comprehensive report on the geochemistry and micromorphology of exceptionally-preserved paleosols and associated fluvial sediments in the Masorobe and Anembalemba members of the Maevarano Formation, which will provide critical insights into paleoclimate; (3) a study focused on trace fossils discovered in the Maevarano Formation, specifically back-filled burrows associated with an entombed carcass (subterranean scavenging); and (4) a study clarifying and formalizing the lithostratigraphy of Upper Cretaceous horizons in the Morondava Basin.

马达加斯加的白垩纪脊椎动物：冈瓦纳生物地理学和板块构造史的一个窗口David Krause，Stoneybrook，CN-1528273 Patrick O 'Conner，俄亥俄州大学，CN-1525915该提案由沉积地质学和古生物学计划（GEO）和非洲、近东南亚计划/国际科学与工程办公室（OD）联合资助。摘要非技术性解释中生代后半期，构成冈瓦纳超大陆南部的陆块结构发生了深刻的变化，对相关的脊椎动物群产生了巨大的影响。马达加斯加位于冈瓦纳的中心附近，因为它分裂成它的组成部分。该提案旨在继续开展一个项目，旨在发现和描述该岛白垩纪地层序列中的脊椎动物化石，分析其古生物学，将其置于系统发育和地质背景中，并将其用于检验与整个冈瓦纳大陆特别是马达加斯加有关的地理和板块构造假说。PI在马达加斯加白垩纪的工作才刚刚开始发挥其潜力。到目前为止，他们已经使岛上晚白垩世脊椎动物的物种多样性增加了五倍，并发现了一些南半球乃至世界上最完整和保存最完整的晚白垩世脊椎动物标本。许多新的分类群已被命名和描述。但是，在马达加斯加广阔的、在古生物学和地质学上未经勘探的白垩纪岩石中，还有很多工作要做。许多分类群只知道零碎的遗骸;许多其他的仍有待发现。随着工作的继续，专业研究者深信马达加斯加的白垩纪脊椎动物群将成为南半球最著名和最具背景的动物群之一，并成为与其他白垩纪冈瓦纳动物群进行比较的主要标准之一。技术说明专业研究者建议继续在马达加斯加西北部马哈赞加盆地的贝里沃特拉研究区收集白垩纪晚期的陆地和淡水脊椎动物化石。马达加斯加，它继续生产鲜为人知的分类群和新分类群的标本的精美材料。虽然他们已经发表了许多详细的解剖学，功能和系统发育分析的类群已知从这个盆地，更多的已经开始和仍然有待完成（特别是在albumloid和amid鱼类，鳄鱼，翼龙，蜥脚类和abelisauroid兽脚类恐龙，鸟类和其他副鸟兽脚类，和哺乳动物）。这项工作的一些将需要组织学采样，从而使生态系统规模的比较分析，元素间的组织学变化在单一的脊椎动物骨骼和测试相关的假设可能的反应和生长历史的适应类群，是遗传学的限制，但表现出广泛的形态和功能的专业化。PI还建议继续开发Mahajanga盆地新发现的油田，这些油田正在产生大致相同年龄但来自不同古环境的新类群。最后，他们建议将他们的努力扩大到马达加斯加西部的Morondava盆地，2010年和2012年的短暂探险取得了重要的发现，并证明了比Mahajanga盆地产生化石的地层更古老的地层的潜力。这些早期层位的发现将提供一个更深的时间背景，以解决地理和板块构造假说。事实上，PI的发现继续对现存和灭绝的马达加斯加动物群的地理历史以及冈瓦纳分裂期间分散和替代的相对重要性产生深远的影响。他们的首要目标之一是提供一个关键的积木重建冈瓦纳古地理的历史，在时间上控制的形式，以及采样的脊椎动物群从马达加斯加的白垩纪在严格的系统发育框架分析，并在准确的古地理重建的背景下。对所有取样层位进行详细的地层学、沉积学和埋藏学研究，以提供时间控制以及古环境和古气候背景，仍然是一个优先事项。更具体地说，PI建议进行：（1）全面分析Maevarano地层埋藏学，为每个主要采石场提供分类摘要和地图，并详细说明Maevarano地层的保存情况？（2）一份关于保存异常完好的古土壤和相关河流沉积物的地球化学和微形态的综合报告，该报告将为古气候提供重要的见解;（3）一项以在Maevarano组中发现的遗迹化石为重点的研究，特别是回填洞穴与埋葬的尸体（地下清除）;（4）研究澄清和正式化的岩石地层上白垩纪地层在Morondava盆地。