浙江长兴志留纪基干盔甲鱼类脑内颅三维重建

Through the field investigation in the Silurian strata of Changxing, Zhejiang Province, we plan to find more early taxa of the Galeaspida (jawless fishes) and additional suitable specimens for the high-resolution computed tomography (HRCT) study. At present, we have reconstructed the nasohypophysial complex of Shuyu, which provided the key evidence for the study of the origin of the jaw. Our preliminary result has been published in Nature. Here, we plan to conduct a further study on galeaspid neurocrania via HRCT, and restore three-dimensional models of neurocrania of two early galeaspid forms. By comparison to the neurocrania of hagfishes, lampreys, osteostracans and gnathostomes, we aim to further understand the key anatomical features of the brain, cranail nerves, and sensory organs.We plan to conduct a further phylogentic analysis of Galeaspida, and discuss in depth the major issues on the origin of the jawed vertebrates.

通过在浙江长兴志留纪地层中进一步的野外发掘工作，发现无颌类盔甲鱼亚纲更多的早期种类以及可用于高分辨率CT扫描（HCT）的脑颅标本。深入开展早期盔甲鱼类的脑颅高分辨率CT研究，重建早期盔甲鱼类2个种类的脑内颅三维模型。目前已完成的浙江曙鱼的鼻垂体系统的三维重建，为探讨颌的起源提供了关键的化石证据， 相关成果已在Nature上发表。在此基础上， 本项目将深入开展早期盔甲鱼类脑内颅的比较解剖学研究，在与无颌类盲鳗亚纲、七鳃鳗亚纲、骨甲鱼亚纲和有颌类脑内颅进行比较的基础上，细致了解早期盔甲鱼类的脑、神经分布、感觉器官等关键解剖学特征， 对盔甲鱼亚纲的系统发育关系和有颌脊椎动物的起源进行深入探讨。

脑颅是脊椎动物系统发育分析中形态学数据最丰富的来源。本项目以江西、浙江志留纪早期盔甲鱼类三维立体保存的脑颅化石为研究对象，应用同步辐射、高精度CT扫描以及计算机三维虚拟重建等目前最先进的技术手段，综合开展志留纪兰多维列世早期盔甲鱼类脑颅的比较解剖学研究。同时，注意结合分子、发育生物学的最新资料，通过多学科交叉、融合，初步解决了以下几个关键问题：1）早期盔甲鱼类脑颅关键特征的演化极向；2）盔甲鱼亚纲的系统发育关系；3）在从无颌到有颌的转变过程中，有颌类如何逐步获得其特征组合。