Paleobiology of the Stem Group Mollusca

软体动物干群的古生物学

• 批准号: 9204080
• 负责人: Bruce Runnegar
• 金额: $ 9万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-15 至 1995-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9204080&HistoricalAwards=false
• 关键词: Paleobiology; Stem; Group; Mollusca

The objective is a new understanding of the origin of the earliest Mollusca and related invertebrates. Recent advances in the study of sclerite-bearing animals from the Cambrian provide an opportunity to investigate the relationship between primitive spiculose molluscs (aplacophorans and chitons) and related soft- bodied phyla (annelids, nemertines, sipunculans). These Cambrian fossils appear to bridge some of the morphological gaps between living phyla and to suggest how mineral skeletons might have first evolved within the Mollusca. We intend to obtain 18S rRNA sequences from living spiculose molluscs in order to test whether aplacophorans are the most primitive living molluscs or are secondarily simplified. Furthermore, we plan to investigate the crystallography of polyplacophoran plates to test the hypothesis that chiton crossed-lamellar aragonite is different from and therefore not homologous to the crossed-lamellar structure of the shelled (conchiferan) molluscs. At the same time we intended to compare the microstructures of molluscan spicules with a variety of sclerites extracted from Cambrian limestones. This work is expected to provide new insights into the early history of the Mollusca and the evolution of the Metazoa as a whole.

其目的是重新认识 最早的软体动物和相关的无脊椎动物。 的最新进展 对寒武纪含骨片动物的研究， 有机会调查原始人 刺状软体动物（无板动物和石鳖）和相关的软体动物， 体门（环节动物，纽形动物，星虫）。 这些寒武纪 化石似乎弥合了一些形态学上的差距， 并提出矿物骨骼可能首先 在软体动物中进化。 我们打算获得18S rRNA 从活的刺状软体动物的序列，以测试 无板动物是最原始的软体动物， 二是简化。 此外，我们计划调查 多囊藻板的晶体学来验证这一假设 石鳖交叉片层文石不同于 因此，不同源的交叉层状结构的 有壳的（贝壳类）软体动物。 与此同时，我们打算 将软体动物骨针的显微结构与各种 从寒武纪石灰岩中提取的片晶。 这项工作是 预计将提供新的见解的早期历史的 软体动物和后生动物作为一个整体的进化。