DISSERTATION RESEARCH: Mammalian Distribution in the Late Cretaceous and Earliest Paleocene Western Interior of North America: Testing Provinciality Through Time

9622771 CLEMENS晚白垩世至最早的古新世（第三纪）时期（7200 - 6000万年前）的洪泛平原和三角洲沉积物，随着西部内陆航道在北美大陆的后退而沉积，记录了哺乳动物进化的非凡时期。 哺乳动物幸存下来，并迅速多样化跨越了白垩纪-第三纪（K/T）边界（6600万年）;许多其他动物群体在这一边界遭受了大规模灭绝。 通过了解这一时期哺乳动物的分布模式，可以解决进化生物学、古生态学和生物地层学领域的许多问题。 最近对这些洪泛平原沉积物中保存的哺乳动物化石的研究表明，在坎帕尼亚晚期（约7200万年），有明显的北方和南方动物群。 这些动物群在接下来的1200万年里保持了独特性吗？ 如果没有，它们在哪些方面发生了变化？ 很难确定基本的模式，部分原因是大量和分散的地理信息，部分原因是对所讨论的动物之间的关系知之甚少。 在威廉·克莱门斯的指导下，新的计算工具将使安妮·威尔首次定量地解决这些问题。 研究的第一阶段将解决化石遗骸中确定的哺乳动物物种之间的系统发育关系问题，包括以前没有考虑过的物种之间的关系。 新的假设将被纳入一个数据库，该数据库是根据整个西部内陆的化石遗址数据编制的。 使用地理信息系统（GIS）来识别地理，环境和分类数据中的空间关联，研究人员将应用常用的不同类型的分析来量化动物群的相似性或变化，并比较结果。 该项目将在三个方面使科学界受益：通过创建一个可供其他研究人员使用的数据库;通过比较动物区系相似性的不同措施;通过创建一个强大的，可测试的和可访问的哺乳动物分布模型跨越K/T边界。

9622771 CLEMENS Floodplain and delta sediments of Late Cretaceous to earliest Paleocene (Tertiary) age (72-60 Million Years Ago), laid down as the Western Interior Seaway retreated across the North American continent, document an extraordinary period of mammalian evolution. Mammals survived and rapidly diversified across the Cretaceous-Tertiary (K/T) boundary (66 MYA); many other groups of animals suffered mass extinctions at this boundary. Many questions in the fields of evolutionary biology, paleoecology and biostratigraphy can be addressed through an understanding of the patterns of mammalian distribution during this time period. Recent studies of fossil mammals preserved in these floodplain sediments indicate that during the Late Campanian (approximately 72 MYA) there were distinct northern and southern faunas. Did these faunas remain distinct in the 12-million year period following? If not, in what respects did they change? It has been difficult to identify basic patterns, partly because of the large and scattered amount of geographic information, and partly because the relationships among the animals in question are poorly understood. Newly available computational tools will allow Anne Wiel, under the supervision of William Clemens, to address these questions quantitatively for the first time. The first stage of the research will address questions of the phylogenetic relationships among the species of mammals identified in the fossil remains, including those among species that have not previously been considered. New hypotheses are to be incorporated in a database compiled from fossil site data from throughout the Western Interior. Using a Geographic Information System (GIS) to recognize spatial associations in this geographic, environmental, and taxonomic data, the investigators will apply different types of analyses commonly used to quantify faunal similarity or variation, and compare the results. This project will benefit the scientific community in three ways: by cre ating a database that will be made available to other researchers; by comparing different measures of faunal similarity; by creating a robust, testable, and accessible model of mammalian distribution across the K/T boundary.