Early Fossil Record and Evolution of Echinoderms and Octocorals - evidences from the Yangtze Platform, China

只有少数海洋动物能被立即识别为棘皮动物：海胆或海星的五重对称是惊人的，这种五重对称的形式使它们与两侧对称的亲戚区别开来。棘皮动物的骨架同样与众不同，由具有典型微观结构（立体）的钙质板构成。但是棘皮动物的代表并不总是具有这些特征，探索它们的早期历史仍然充满争议。现代棘皮动物的元古代起源，特别是自由生活的代表（拟刺虫），是不清楚的。在珊瑚虫刺胞动物中也发现了类似的情况。八爪珊瑚的化石记录可以追溯到新元古代，在埃迪卡拉动物群中有似五爪珊瑚的生物；但这些分类群的关系仍在争论中。据推测，前寒武纪棘皮动物的茎群可能是由缺乏钙质体板的非五径向或非径向生物组成的。与更普遍的认为盘藻门是盘藻门的最早代表的观点相反，人们认为柳珊瑚和藻藻门的盘藻是最早的盘藻门刺胞动物之一，而现代盘藻门的盘藻是高度进化的生物，最早发现于中生代。扬子地台是一个世界范围内独特的位置，我们有机会解决早期后生动物辐射和相关生物矿化的问题。基于新的和尚未应用于逻辑提取的微古生物学方法，通过宏观古生物学和微古生物学研究的结合，我们计划填补刺皮动物和八爪珊瑚早期化石记录不完整和不了解的空白。

Only few marine animals are immediately recognizable as echinoderms: the fivefold symmetry of a sea urchin or starfish is striking, and this pentaradiate form sets them apart from their bilaterally symmetrical relatives. The echinoderm skeleton is equally distinctive, being made of calcitic plates with a typical microstructure (stereom). But representatives of the Echinodermata have not always possessed these features, and exploring their early history remains highly controversial. The Proterozoic origin of the modern echinoderm bauptan, especially of the free-living representatives (Eleutherozoa), is unclear. Similar conditions have been found within the anthozoan cnidarians. The fossil record of octocorals traces back into the Neoproterozoic time with pennatulid-like organisms in various Ediacara biota; but relationships of these taxa are still under debate. It is assumed that the Precambrian stem group of echinoderms were probably comprised of nonpentaradial or non-radial organism lacking calcitic stereom plates. In contrast to the far more common opinion that the Pennatulacea are the first representatives of the Octocorallia, it is assumed that gorgonaceous and alcyonacean octocorals are one of the first octocorallian cnidarians, and the modern pennatulacean octocorals are highly evolved organisms, first known since the Mesozoic. The Yangtze Platform is a worldwide unique location where we have the chance to solve problems and questions of early metazoan radiation and related biomineralisation. Based on new and not yet applied micropalae onto logical extraction methods and through the combination of macro- and micropalaeontological investigations we plan to fill a gap in the incomplete and poorly understood early fossil record of echinoderms and octocorals.