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

9622771晚白垩世至早古新世(第三纪)的克莱门斯泛滥平原和三角洲沉积物(7200万-6000万年前)，随着西部内陆海道在北美大陆的撤退而沉积，记录了哺乳动物进化的非凡时期。哺乳动物幸存下来，并在白垩纪-第三纪(K/T)界线(66 MYA)上迅速多样化；许多其他动物群体在这条界线上遭受了大规模灭绝。通过了解哺乳动物在这一时期的分布模式，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72年)，存在明显的北部和南部动物群。在接下来的1200万年里，这些动物群是否仍然保持着鲜明的特色？如果不是，他们在哪些方面发生了变化？识别基本的模式一直很困难，部分原因是大量而分散的地理信息，部分原因是人们对所讨论的动物之间的关系知之甚少。最新可用的计算工具将使安妮·威尔在威廉·克莱门斯的监督下首次定量解决这些问题。研究的第一阶段将解决在化石遗骸中发现的哺乳动物物种之间的系统发育关系问题，包括以前没有被考虑的物种之间的系统发育关系。新的假设将被纳入到一个数据库中，该数据库由整个西部内陆的化石遗址数据汇编而成。使用地理信息系统(GIS)识别地理、环境和分类数据中的空间联系，调查人员将应用不同类型的分析，通常用于量化区系相似性或变异，并比较结果。该项目将在三个方面惠及科学界：通过创建一个可供其他研究人员使用的数据库；通过比较不同的动物群相似性度量；通过创建一个健壮的、可测试的、可访问的跨K/T边界的哺乳动物分布模型。

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.