ABSTRACT The haptophyte genus Pseudohaptolina (formerly Chrysochromulina clade B1-3) currently harbours two species: Pseudohaptolina arctica and Pseudohaptolina sorokinii. In addition, Chrysochromulina birgeri is expected to belong to this genus due to its morphological similarity to P. sorokinii, but it has not yet been genetically characterised. A strain belonging to Pseudohaptolina was brought into culture from Arctic waters, characterised by 18S and 28S rRNA gene sequencing as well as optical and transmission electron microscopy, and deposited in the Roscoff Culture Collection with the code RCC5270. Molecular and morphological data from RCC5270 were compared with those from previously described Pseudohaptolina and Pseudohaptolina-like species. Strain RCC5270 showed strong phylogenetic affinity to P. sorokinii, but observations using transmission electron microscopy (TEM) showed that RCC5270 possesses three types of organic body scales, rather than two as originally described for P. sorokinii. We found that the occurrence of three scale types is likely to have been overlooked in the original descriptions of both P. sorokinii and C. birgeri. We also found that environmental metabarcodes identical to the sequence of RCC5270 were abundant at the location from which C. birgeri was initially described (Gulf of Finland). We conclude that P. sorokinii and C. birgeri are conspecific and P. sorokinii is therefore synonymous with C. birgeri. Based on its phylogenetic placement and nomenclatural priority, we propose the new combination Pseudohaptolina birgeri and emend the description of this species.

中文翻译：

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Pseudohaptolina birgeri 梳的分类重新分配。十一月 （触生植物）

摘要 触须藻属 Pseudohaptolina（原 Chrysochromulina clade B1-3）目前有两个物种：Pseudohaptolina arctica 和 Pseudohaptolina sorokinii。此外，由于其与 P. sorokinii 的形态相似性，预计 Chrysochromulina birgeri 属于该属，但尚未对其进行遗传表征。一株属于 Pseudohaptolina 的菌株从北极水域培养，通过 18S 和 28S rRNA 基因测序以及光学和透射电子显微镜进行表征，并以代码 RCC5270 保藏在罗斯科夫培养物保藏中心。将 RCC5270 的分子和形态学数据与先前描述的 Pseudohaptolina 和 Pseudohaptolina 类物种的数据进行比较。菌株 RCC5270 对 P. sorokinii 表现出很强的系统发育亲和力，但使用透射电子显微镜 (TEM) 进行的观察表明，RCC5270 拥有三种类型的有机体鳞片，而不是最初描述的 P. sorokinii 中的两种。我们发现在 P. sorokinii 和 C. birgeri 的原始描述中可能忽略了三种尺度类型的出现。我们还发现与 RCC5270 序列相同的环境元条形码在最初描述 C. bilgeri 的位置（芬兰湾）处很丰富。我们得出结论，P. sorokinii 和 C. biorgeri 是同种的，因此 P. sorokinii 与 C. biorgeri 是同义词。基于其系统发育位置和命名优先级，我们提出了新的组合 Pseudohaptolina birgeri 并修改了对该物种的描述。