Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, College of Life Science, South China Normal University, West 55 of Zhongshan Avenue, Guangzhou, 510631, China.
The Eighth Geological Brigade, Hebei Geological Prospecting Bureau, Qinhuangdao, 066001, China.
J Phycol. 2019 Feb;55(1):104-117. doi: 10.1111/jpy.12807. Epub 2018 Nov 26.
Monoclonal strains of Chaetoceros species were collected from Chinese warm waters. Vegetative cells and resting spores were examined using light microscopy as well as scanning and transmission electron microscopy. Combined morphological and DNA sequence data from the hypervariable D1-D3 region of the nuclear ribosomal large subunit showed the presence of two new species within the section Compressa, herein described as Chaetoceros bifurcatus sp. nov. and C. millipedarius sp. nov. Both species possessed features typical of the section Compressa, but C. bifurcatus was characterized by the heavy intercalary setae fusing and extending together for a distance before diverging. The heavy setae were not visually contorted, lacking poroids and spines, in contrast with how the section Compressa has been defined. Chaetoceros millipedarius was characterized by a horizontal stagger of ordinary intercalary setae when the chain was seen in broad girdle view, making the chain look like a millipede. The two new species were supported by molecular phylogenetic analyses with C. bifurcatus sister to C. contortus var. ornatus, while C. millipedarius was sister to C. contortus var. contortus. Based on the morphological features exhibited in C. bifurcatus, the diagnosis of the section Compressa was emended to exclude "contorted" heavy setae and compressed valve faces.
从中国暖水中采集了 Chaetoceros 物种的单克隆株。使用光学显微镜以及扫描和透射电子显微镜检查了营养细胞和休眠孢子。来自核核糖体大亚基高变区 D1-D3 区域的形态学和 DNA 序列数据的组合表明，在 Compressa 节中存在两个新种，本文将其描述为 Chaetoceros bifurcatus sp. nov. 和 C. millipedarius sp. nov. 这两个物种都具有 Compressa 节的典型特征，但 C. bifurcatus 的特征是附加的粗刺融合并一起延伸一段距离后再分叉。粗刺没有视觉上的扭曲，没有孔和刺，这与 Compressa 节的定义不同。 Chaetoceros millipedarius 的特征是在宽腰带视图中观察到链时，普通附加刺的水平交错，使链看起来像千足虫。这两个新种得到了分子系统发育分析的支持，C. bifurcatus 与 C. contortus var. ornatus 姐妹关系，而 C. millipedarius 与 C. contortus var. contortus 姐妹关系。基于 C. bifurcatus 表现出的形态特征，对 Compressa 节的诊断进行了修订，以排除“扭曲”的粗刺和压缩的阀面。
