The Pliocene "Pinecrest" Bivalve Mollusk Fauna: Taxonomy, Environmental Stratigraphy, Geochronology and Biogeography

这是对一个动物群化石的多方面研究，该动物群由大约200种海洋双壳软体动物组成，这些软体动物在最近的冰河时代之前居住在佛罗里达州南部，在冰河时代遭受了严重灭绝。这种动物被保存在萨拉索塔采石场暴露的贝壳床中，令人惊叹。PI正在对大范围的贝壳床进行测绘。利用幸存物种的栖息地和贝壳床的物理性质的信息，Pi得出结论，贝壳床代表了障碍岛(或唾液)和泻湖环境的复合体。进一步的工作将允许检验关于贝壳床不寻常的垂直序列是如何发展的假说。该动物群是一个大型海洋动物群的热带组成部分，该动物群占据了美国整个东部和墨西哥湾海岸。从佛罗里达州北部到弗吉尼亚州，该动物群的组成部分得到了很好的研究。通过研究热带部分来完成这幅图，将使我能够调查冰河时代灭绝和迁徙的地理模式。为此，派将利用博物馆的一般藏品、他自己的藏品和模式标本，并在适当的情况下使用形态计量学，完成对南佛罗里达动物的物种水平分类研究。传统上分配给这些动物的确切年龄最近受到了质疑。PI将试图通过对珊瑚化石的放射性测年和基于软体动物和微化石的生物地层学来解决这个问题。

This is a multifaceted study of a fossil fauna comprising about 200 species of marine bivalve mollusks that occupied southern Florida prior to the recent ice age and that suffered heavy extinction during the ice age. This fauna is spectacularly preserved in shell beds exposed by quarrying at Sarasota. PI is mapping the shell beds over a large area. Using information about habitats of surviving species and the physical nature of the shell beds, PI has concluded that the beds represent a complex of barrier island (or spit) and lagoonal environments. Further work will allow testing of hypotheses as to how the unusual vertical sequence of shell beds developed. The fauna is the tropical component of a large marine fauna that occupied the entire East and Gulf coasts of the U.S. Components of the fauna from northern Florida to Virginia are well studied. Completing the picture by studying the tropical component will enable me to investigate geographic patterns of extinction and migration during the ice age. To this end, PI will complete a species- level taxonomic study of the south Florida fauna, using general museum collections, his own collections, and type specimens--and employing morphometrics where appropriate. The precise age traditionally assigned to the fauna has recently been questioned. PI will attempt to resolve the issue using radiometric dating of fossil corals and biostratigraphy based on mollusks and microfossils.