Early Evolution of Ligaments and Shell Microstructure in the Bivalvia, with a Comprehensive, Polythetic, Phylogenetic Analysis

双壳类韧带和壳微结构的早期演化及其系统发育分析约瑟夫·G卡特，北卡罗来纳州查佩尔山大学 虽然韧带和壳的显微结构是双壳类的系统发育信息的重要来源，这些功能仍然知之甚少，大多数早，中古生代属和种。 最近在肯塔基州的奥陶纪双壳类和哥特兰岛的志留纪双壳类中发现了残留的文石韧带和贝壳微结构，这表明这些特征可能在整个中生代都有迹可循。 资助的研究将开发一个广泛的古生代双壳韧带和壳微结构数据库，重点是代表美国，加拿大北极，瑞典，撒丁岛，捷克共和国，中国，澳大利亚，新西兰和南极洲的地区的选定古生代动物群。 然后，这些数据将结合其他古生物学数据和有限的软解剖推断，提供一系列的分类学上全面的，严格的系统发育分析的古生代双壳类的基础上简约，可能性和距离的方法，测试对地层数据，传统的进化系统学，和现代分子系统发育。 最后的系统发育合成将用于修订古生代双壳类的系统发育分类。 除了阐明韧带和壳微结构的早期演化外，这项研究将有助于解决双壳类演化中的许多悬而未决的问题，并为以后古生代后双壳类的系统发育分析提供坚实的基础。

ABSTRACTEarly Evolution of Ligaments and Shell Microstructure in the Bivalvia, with a Comprehensive, Polythetic, Phylogenetic AnalysisDr. Joseph G. Carter, University of North Carolina at Chapel Hill Although ligaments and shell microstructures are important sources of phylogenetic information for the Bivalvia, these features remain poorly known for most early and middle Paleozoic genera and species. The recent discovery of relict aragonitic ligaments and shell microstructures in Ordovician bivalves from Kentucky and in Silurian bivalves from Gotland suggests that these features may be traceable throughout the Phanerozoic. The funded research will develop an extensive database of Paleozoic bivalvian ligament and shell microstructure, focusing on selected Paleozoic faunas representing localities in the United States, Arctic Canada, Sweden, Sardinia, the Czech Republic, China, Australia, New Zealand, and Antarctica. These data will then be combined with other paleontological data and limited inferences of soft anatomy to provide a series of taxonomically comprehensive, rigorously phylogenetic analyses of Paleozoic bivalves based on parsimony, likelihood, and distance methods, tested against stratigraphic data, traditional evolutionary systematics, and modern molecular phylogenies. The final phylogenetic synthesis will be used for a revised phylogenetic classification of Paleozoic bivalves. In addition to clarifying the early evolution of ligaments and shell microstructures, this research will help resolve many outstanding questions of bivalve evolution, and will provide a firm foundation for future phylogenetic analyses of post-Paleozoic bivalves.