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.

目的是对最早的软体动物和相关无脊椎动物的起源的新理解。 来自寒武纪的含硬化物动物的研究的最新进展为研究了原始的spiculose软体动物（aplacophorans and chitons and Chitons）与相关的软体门（Annelids，nemertins，nemertines，sipunculans）之间的关系提供了机会。 这些寒武纪化石似乎弥合了生命门之间的一些形态差距，并暗示了矿物骨骼如何首先在软体动物中进化。 我们打算从活体性小软体动物中获得18S rRNA序列，以测试同性恋者是否是最原始的活软体动物或次要简化。 此外，我们计划研究多氯酚板的晶体学，以测试Chiton交叉层的Aragonite的假设与所壳（Conchiferan）软体动物的跨层结构不同，因此与跨层结构不同。 同时，我们打算将软体动物spicules的微观结构与从寒武纪石灰石中提取的多种硬化矿进行比较。 预计这项工作将为软体动物的早期历史和整个Meltazoa的发展提供新的见解。