Cyclotella lacuskarluki Manguin ex Kociolek & Reviers is a small diatom known only from the original drawing that provides little information on the morphology of this taxon. As Manguin’s original materials are lost, recently collected samples from Lake Karluk, Alaska, the type locality of the species, were studied with light and scanning electron microscopy to determine its identity. As a result of this investigation, C. lacuskarluki is transferred here to the genus Discostella. Discostella lacuskarluki is 2.5–7 µm in diameter, has a shallow mantle, a stellar pattern of alveoli in the valve centre that may be reduced or completely absent, bifurcating costae and 4–5 marginal fultoportulae opening externally by short thickened tubes with round openings. We observed this species in numerous lakes across Alaska, in Lake Tahoe, Nevada, in several lakes across Canada, and in tundra and tree-line lakes of Northeastern Siberia. Although direct comparison with other Discostella species is difficult because the small size of these diatoms requires high-resolution imagery to reveal ultrastructural details, it appears that D. lacuskarluki is conspecific with D. tatrica Procházková et al. recently described from lakes of Central Europe and also reported from the European part of Russia. It is also conspecific with D. nipponica (Skvotzov) Tuji & D. M. Williams known from Japan. The apparent wide distributional range of this species indicates that it has been overlooked and commonly reported as D. pseudostelligera or D. stelligera in arctic, boreal and alpine lakes.

中文翻译：

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Discostella lacuskarluki (Manguin ex Kociolek & Reviers) 梳子。十一月：北极和北方湖泊常见的纳米浮游硅藻

Cyclotella lacuskarluki Manguin ex Kociolek & Reviers 是一种小型硅藻，仅从原始绘图中得知，它提供的关于该分类群形态的信息很少。由于 Manguin 的原始材料丢失，最近从该物种的类型所在地阿拉斯加卡鲁克湖收集的样本通过光学和扫描电子显微镜进行了研究，以确定其身份。作为这项调查的结果，C. lacuskarluki 被转移到 Discostella 属。Discostella lacuskarluki 的直径为 2.5-7 µm，具有浅地幔，瓣膜中心的星形肺泡可能减少或完全消失，分叉肋骨和 4-5 个边缘的 fultoportulae，由带有圆形开口的短加厚管向外开口。我们在阿拉斯加的许多湖泊、内华达州的太浩湖、在加拿大的几个湖泊以及西伯利亚东北部的苔原和林线湖泊中。尽管与其他 Discostella 物种的直接比较很困难，因为这些硅藻的小尺寸需要高分辨率图像来揭示超微结构细节，但 D. lacuskarluki 似乎与 D. tatrica Procházková 等人是同种的。最近在中欧的湖泊中描述过，也从俄罗斯的欧洲部分报道过。它也与日本已知的 D. nipponica (Skvotzov) Tuji & DM Williams 同种。该物种明显的广泛分布范围表明它在北极、北方和高山湖泊中被忽视并普遍报道为 D.pseudostelligera 或 D. stelligera。尽管与其他 Discostella 物种的直接比较很困难，因为这些硅藻的小尺寸需要高分辨率图像来揭示超微结构细节，但 D. lacuskarluki 似乎与 D. tatrica Procházková 等人是同种的。最近在中欧的湖泊中描述过，也从俄罗斯的欧洲部分报道过。它也与日本已知的 D. nipponica (Skvotzov) Tuji & DM Williams 同种。该物种明显的广泛分布范围表明它在北极、北方和高山湖泊中被忽视并普遍报道为 D.pseudostelligera 或 D. stelligera。尽管与其他 Discostella 物种的直接比较很困难，因为这些硅藻的小尺寸需要高分辨率图像来揭示超微结构细节，但 D. lacuskarluki 似乎与 D. tatrica Procházková 等人是同种的。最近在中欧的湖泊中描述过，也从俄罗斯的欧洲部分报道过。它也与日本已知的 D. nipponica (Skvotzov) Tuji & DM Williams 同种。该物种明显的广泛分布范围表明它在北极、北方和高山湖泊中被忽视并普遍报道为 D.pseudostelligera 或 D. stelligera。tatrica Procházková 等人。最近在中欧的湖泊中描述过，也从俄罗斯的欧洲部分报道过。它也与日本已知的 D. nipponica (Skvotzov) Tuji & DM Williams 同种。该物种明显的广泛分布范围表明它已被忽视，在北极、北方和高山湖泊中通常被报告为 D. pseudostelligera 或 D. stelligera。tatrica Procházková 等人。最近在中欧的湖泊中描述过，也从俄罗斯的欧洲部分报道过。它也与日本已知的 D. nipponica (Skvotzov) Tuji & DM Williams 同种。该物种明显的广泛分布范围表明它在北极、北方和高山湖泊中被忽视并普遍报道为 D.pseudostelligera 或 D. stelligera。