论文部分内容阅读
基于对53个形态学特征的讨论,首次开展了无颌类儒甲鱼亚纲的简约性分析,获得了3 个最简约的分支图,其步长为126,一致性指数为0．508,保留指数为0．801。在此基础上,修订了盔甲鱼亚纲的分类。研究结果表明,志留纪兰多维列世至温洛克世的汉阳鱼类、修水鱼类和大庸鱼类属于盔甲鱼亚纲的基干类群。在其余盔甲鱼类中,识别出3个大的单系类群, 分别是真盔甲鱼目、多鳃鱼目和华南鱼目。在盔甲鱼亚纲中,头甲背窗的起源至少发生了两次,一次在多鳃鱼目支系中,另一次在华南鱼目支系中。基于背窗特征而建立的大窗鱼类并不是一个单系类群。盔甲鱼类的年代分布指示该类群的两次辐射演化,分别是兰多维列世特列奇期基干盔甲鱼类和真盔甲鱼目的辐射演化,和早泥盆世洛霍考夫期多鳃鱼目和华南鱼目的辐射演化。
Based on the discussion of 53 morphological traits, the simple analysis of the jawless mitefish subclass was carried out for the first time. The three most simple branch graphs were obtained, with a step length of 126 and a consistency index of 0.508. The index is 0.801. On this basis, revised the classification of armor fish subclass. The results showed that the Hanyang fish, water-cut fish and big-yelong fish from the Silurianland to the Lochrajids belong to the basic group of the armor subclass. Among the remaining armor fishes, three large monophyletic groups were identified, namely Trichoplus, Trichomes and Southern China. In the armor subclass, the origin of the dorsal head window has occurred at least twice, once in the gill fishes, and once again in the fishes in southern China. The large window fish established based on back-window features is not a monophyletic group. The age distribution of armor fishes indicates the evolution of the two radiatives of this group, namely the radiant evolution of the Trinidad and Tobago armorfish and the true armorfish, respectively, Head and South China Fish Radiation Evolution.