Abstract: Molecular systematics is used to sequence the sclecractinian corals' 18S rDNA and to discuss the evolution and classification, in comparison with the classic systematics based on the skeletal morphology and microstructure. Concerning the classification of the suborders, families and genera, and evolution of the Scleractinian corals, two major conclusions can be drawn: 1) Scleractinia had at least two major clades in their early evolution, as indicated by the morphological classification and former molecular systematics. Although the two major clades indicated by both analysis are not exactly the same, they all propose that there is strong division among the suborders of the Order Scleractinia. 2) The five suborders of Scleractinia, Fungiina, Faviina, Caryophylliina and Dendrophylliina are not all monophyletic, and this throws doubt upon the classification of Wells' traditional suborders. Although molecular data basically support clustering the species into traditional morphologically-based genera and families, there are still some disagreements in the classification of some families, e.g. the Family Rhizangiidae within Suborder Faviina and the Family Dedrophylliidae within Suborder Dendrophylliina.

Key words: Scleractinia, molecular biology, phylogeny, systematics

摘要： 用分子生物学方法测定石珊瑚目一些现代种类的18S rDNA，构建石珊瑚的系统发生树，并且对石珊瑚目中一些亚目和科属的演化关系进行分子生物学和传统的比较形态学的对照研究，以期为石珊瑚起源和演化提供新的证据。研究表明： 1） 石珊瑚的早期演化至少有两个主要演化分支，这支持以前的形态分类研究和分子生物学研究的结果。尽管这两方面研究所得出的分支不尽相同，但都说明石珊瑚目的亚目一级有强烈分化； 2） 石珊瑚目的5个亚目不全是单系发生的，对Wells的传统分类提出了质疑。此项分子生物研究虽与大部分种的属和科级根据形态生物学的归属相符合，但还有些科的归属还有分歧，如Faviina亚目中的Rhizangiidae科和Faviina亚目中的Dendrophylliidae科等。

关键词: 石珊瑚, 分子生物学, 系统演化, 分类