若干寒武纪三叶虫类群躯体分节进化发育模式

项目名称： 若干寒武纪三叶虫类群躯体分节进化发育模式

项目编号： No.41272027

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 张喜光

作者单位： 云南大学

项目金额： 90万元

中文摘要： 分节的躯干和附肢是节肢动物最显著的形态特征，其蕴含的基本信息，历来被认为有着潜在重要的系统分类和进化意义。三叶虫是古生代最常见的节肢动物，然而，至今我们对其寒武纪许多代表支系的基本躯体构建、个体发育及早期辐射分异仍感模糊并存在种种争议。大量来自华南寒武系精美保存的磷酸盐化盘虫三叶虫显示：其背壳的一些细微构造，如小刺、腺孔和瘤粒，与其体节大致存在一一对应的内在联系。基于此，依据源自其个体发育和微观形态解剖证据，借鉴三维保存的奥斯坦型（Orsten-type）节肢类随生长显现的详尽形态、结构变异（包括躯干的分节）规律，以识别盘虫三叶虫不同属种体节的增生方式，确认该类群的基本分节模式，并与其它一些个体发育得到详尽研究的三叶虫的躯体分节综合比较，辨析它们分节模式可能存在的异同。从而以合符逻辑、富于新意的思路，探讨这些三叶虫类群的发育、演化和系统分类，力争在理论上能有所突破。

中文关键词： 三叶虫；节肢动物；进化；发育生物学；寒武纪

英文摘要： Arthropods are characterized by a segmented body with hardened exoskeletons and jointed appendages, from which derived anatomic data are conventionally regarded as being potentially significant in their systematic and evolutionary studies. Abundant and highly diversified trilobites have been well discovered throughout the Paleozoic, consisting of one of the most distinct arthropod groups. However, our knowledge about the evolutionary development of trunk segmentation of many trilobite branches during the Cambrian radiation is scarce, and hypotheses on this aspect remain controversial. Based on numerous phosphatized eodiscoid exoskeletons collected from the Cambrian of southern China, in this study we attempt to verify some skeletal microstructures, such as tiny marginal spines, gland pores and bristles (or setae), may come into being in accordance with the development of trunk segments. That is, the relatively easy determination of such microstructures may offer a reliable way to mark the trunk segments during ontogenetic development. On this basis, this study, as relying on convincing information derived from their own ontogenetic and anatomic analyses, along with inference of soft body anatomy of some contemporaneous arthropods with Orsten-type preservation, may substantially reveal the essential mode of trunk

英文关键词： trilobites；arthropods；Evolution；development；Cambrian