异角毛藻和平滑角毛藻的分类学修订

Taxonomic Revision of Chaetoceros diversus and C. laevis

摘要:

为了澄清异角毛藻和平滑角毛藻的分类学疑问，在广东南澳岛海域建立了单克隆培养株系，利用光学显微镜和电子显微镜技术，开展了基于生活史的连续形态学观察，发现粗大角毛的延伸方向易变，是不稳定特征，不宜继续赋予分类学价值。对核糖体大亚基编码基因的D1~D3区序列进行扩增和分析，结果异角毛藻和平滑角毛藻的目标基因序列基本一致，仅有1个平滑角毛藻株系存在2个差异碱基。因此，两者具有一致的系统学位置，属于同一物种，平滑角毛藻应该是异角毛藻的同种异名。

Abstract:

In order to clarify the taxonomic issues between Chaetoceros diversus Cleve and C. laevis Leuduger-Fortmorel, their monoclonal strains were established near Nanao Island region, Guangdong Province. The continuous morphology of them was observed during all life stages under light and electron microscopies. The results showed that the extending direction of the thick setae were various in different life stages, so that they are not constant and can't be considered as useful taxonomic features. The D1-D3 sequence of the large subunit encoding ribosomal gene was amplified and analyzed. The results showed that the strains of C. diversus and C. laevis have the coincident sequences except only two differential bases in one strain of C. laevis. Chaetoceros diversus and C. laevis have uniform phylogenetic position in molecular tree, which indicates that they belong to the same species. Therefore, C. laevis is proposed as the synonym of C. diversus.