Morphology of some fossil lacustrine centric species from the western United States assigned to the genus Cyclotella (Bacillariophyta), including four described as new
Morphology of some fossil lacustrine centric species from the western United States assigned to the genus Cyclotella (Bacillariophyta), including four described as new
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DOI：
10.11646/phytotaxa.127.1.11
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发表时间：
2013-08
期刊：
影响因子：
1.1
通讯作者：
J. Kociolek;G. Khursevich
中科院分区：
文献类型：
--
作者：
J. Kociolek;G. Khursevich
在研究美国西部许多非海洋地区的化石中心硅藻时，我们遇到了四个新种和两个已知的分类群，它们应该被归类为Cyclella(F.T.Kutzing)A.de BreBisson属。我们详细描述了这些物种的形态特征，并讨论了它们与环藻其他成员的相关性。在光学显微镜和扫描电子显微镜下对这些化石种进行了研究，主要根据肺泡的结构以及轮缘孔(E)和边缘黄托的位置(S)，可将它们划分为几个形态群。在所有这些环藻分类群中，都存在内穹顶筛孔和外孔的室状乳晕，或在中心区域同时存在乳晕和瓣膜表面的黄褐斑。
During consideration of fossil centric diatoms from a variety of non-marine localities in the western USA, we encountered four new species and two previously known taxa that should be assigned to the genus Cyclotella (F.T. Kutzing) A. de Brebisson . We detail the morphological features of these species, and discuss their relevance to other members of the Cyclotella . These fossil species are studied in light and scanning electron microscopes, and can be assigned to several morphological groups with respect mainly to the structure of alveolae as well as positon(s) of rimoportula(e) and marginal fultoportulae. Presence of loculate areolae with internal domed cribra and external foramina, or both areolae and valve face fultoportulae in the central area are characteristics found in all of these Cyclotella taxa.