The species concept in a marine diatom: LSU rDNA–based phylogenetic differentiation in Skeletonema marinoi/dohrnii (Bacillariophyceae) is not reflected in morphology
The species concept in a marine diatom: LSU rDNA–based phylogenetic differentiation in Skeletonema marinoi/dohrnii (Bacillariophyceae) is not reflected in morphology
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海洋硅藻的物种概念：Skeletonema marinoi/dohrnii（硅藻纲）中基于 LSU rDNA 的系统发育分化并未反映在形态中
作者：
M. Ellegaard;Anna Godhe;Karolina Härnström;M. McQuoid
M. Ellegaard，A.戈德，K. Härnström和M.麦奎德2008.海洋硅藻的物种概念：LSU rDNA为基础的系统发育分化的Marinoi/dohrnii（Bacillariophyceae）是不反映在形态。Phycologia 47：156 - 167. DOI：10.2216/07 - 09.1普遍存在的海洋硅藻属双丝藻包括几个新描述的物种。本文对其中的一个新种--海洋短丝藻（Acetonema marinoi）的形态学和LSU序列多样性进行了研究。研究中包括的15个单克隆菌株（来自瑞典西海岸，瑞典东海岸，葡萄牙和加拿大）显示出形态种内LSU rDNA序列的差异，甚至在从单个浮游生物网样本建立的克隆中也存在差异。在形态学上，所有克隆彼此之间以及与密切相关的物种多氏刺丝线虫之间无法区分。在这两个物种的原始描述中，它们是通过环带的结构来区分的。然而，这两个种的环带类型几乎都出现在所有的克隆的单个样品中。在这项研究中，Marinoi。基于LSU的系统发育与分成两个物种的分裂是一致的，并且它们的地理分布可能存在差异。因此，我们目前不建议将这两个物种合并。关于原生生物内的物种界定和神秘物种的问题往往出现在这样的研究，包括形态和DNA序列分析的数据，这些问题在这里得到解决。
M. Ellegaard, A. Godhe, K. Härnström and M. McQuoid. 2008. The species concept in a marine diatom: LSU rDNA–based phylogenetic differentiation in Skeletonema marinoi/dohrnii (Bacillariophyceae) is not reflected in morphology. Phycologia 47: 156–167. DOI: 10.2216/07-09.1 The ubiquitous marine diatom genus Skeletonema includes several newly described species. This paper presents a study of morphology and LSU sequence diversity of one of these new species, Skeletonema marinoi. The 15 monoclonal strains (from the Swedish west coast, the Swedish east coast, Portugal and Canada) included in the study showed differences in LSU rDNA sequence within the morphospecies, with differences seen even among clones established from a single plankton net sample. Morphologically, all clones were indistinguishable from each other and from the closely related species Skeletonema dohrnii. In the original description of these two species, they were differentiated by the structure of the girdle bands. However, the girdle band types of both species were found within single samples of almost all clones of S. marinoi in this study. The LSU-based phylogeny is consistent with the split into two species, and there may be a difference in their biogeographical distribution. We therefore do not at present suggest that the two species be merged. Questions regarding species delimitation and cryptic species within protists often arise from such studies that include data from both morphological and DNA sequence analysis, and such questions are addressed here.