TAXONOMIC INTERPRETATION OF THE RIMOPORTULA OF FRESHWATER GENERA IN THE CENTRIC DIATOM FAMILY THALASSIOSIRACEAE
TAXONOMIC INTERPRETATION OF THE RIMOPORTULA OF FRESHWATER GENERA IN THE CENTRIC DIATOM FAMILY THALASSIOSIRACEAE
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DOI：
10.1080/0269249x.1987.9705003
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发表时间：
1987
期刊：
影响因子：
1.8
通讯作者：
E. Theriot;E. Stoermer;H. Håkansson
中科院分区：
文献类型：
--
作者：
E. Theriot;E. Stoermer;H. Håkansson
很难描述环藻、环藻和环藻--海链藻科三个分类上最多样化的、主要是淡水的属。Cylostephanos最早的特征是其外部有一束状条纹和辐射状的肋骨，内部呈环藻状，靠近边缘有小室。在Cyclstephanos的产生之后，Cyclella和Stephanodisus都被诊断为缺乏字符。然而，这项研究表明，大多数环尾轮虫和斯蒂芬迪斯物种可以根据它们不寻常的轮孔形态进行分类。已知的环藻属物种中，超过一半的物种，包括选型种，在脊骨下面有脊孔；我们称之为‘脊椎下’物种群。所有已知的环藻属物种的边缘孔都没有长长的外管，无论其位置如何，尽管有些可能在外部开口周围有一个小的凸起的环状结构。相比之下，斯蒂芬诺迪克斯等人的选型……
It is difficult to delineate Cyclotella, Cyclostephanos and Stephanodiscus—the three most taxonomically diverse, predominantly freshwater genera of the Thalassiosiraceae. Cyclostephanos was originally distinguished by a Stephanodiscus-like exterior of fasciculate striae and raised radiating costae, and a Cyclotella-like interior, with chambers near the margin. After the creation of Cyclostephanos, Cyclotella and Stephanodiscus were each diagnosed by absence of characters. However, this study suggests that most Cyclostephanos and Stephanodiscus species can be classified on the basis of their unusual rimoportula morphology. Over half of the Cyclostephanos species known, including the lectotype, have the rimoportula underneath a spine; we call this the ‘subspina’ species group. The rimoportula of all known Cyclostephanos species lacks a long external tube, regardless of its location, although some may have a small raised annulus around the external opening. In contrast, the lectotype of Stephanodiscus and al...