Characterizing Metazoa of the Neoproterozoic by Investigating the Taphonomy and Phylogeny of Modern Animals

这项研究将解决与动物早期历史相关的三个方面的问题：新元古代遗迹化石及其制造者的性质；现代遗迹和软体动物的化石分类；以及后生动物基础支系的系统发育。它将继续对新元古代和现代痕迹生物进行比较研究，对双胞胎后生动物的遗体化石和现代化石进行比较观察，并对早期分枝后生生物群进行分子系统学分析。尽管许多研究人员假设新元古代遗迹化石是由双边动物形成的，但前两国动物的双倍体动物也可以做出类似的痕迹。同样，许多现代蛇形动物，虽然没有骨骼，但有坚硬的和/或致密的身体，这将成为与一些新元古代身体化石进行实验挖掘比较的基础。对基本后生动物的分子测序表明，双侧动物是胎盘动物的姐妹群，而线虫是这两个群的姐妹。这项提案中概述的工作将检验这些假设，并制定适当的新假设。

9814845Valentine This research will address three aspects of problems related to the early history of animals: the nature of Neoproterozoic trace fossils and their makers; the taphonomy of modern traces and soft-bodied animals; and the phylogeny of basal metazoan clades. It will continue comparative studies of Neoproterozoic and modern trace-making organisms, comparative observations of body fossils and modern taphonomy of diploblastic metazoans, and the molecular phylogenetic analysis of the early branching metazoan groups. Although many investigators have assumed that Neoproterozoic trace fossils were made by bilaterian animals, pre-bilaterian diploblastic animals can make similar kinds of traces. Likewise, many modern cnidarians, although unskeletonized, have rigid and/or dense bodies that will form the basis for experimental taphonomic comparisons to some Neoproterozoic body fossils. Molecular sequencing of basal metazoans suggests that bilaterians are the sister group to placozoans, and that cnidarians are sister to these two groups combined. The work outlined in this proposal will test these hypotheses and develop appropriate new ones.