We used light and electron microscopy to characterize a Late Miocene freshwater diatomite deposit in the Chalk Hills Formation, near Payette, Idaho, USA. The diatom assemblage from this sample was nearly monotypic, dominated by a single taxon with similarities to Lindavia bodanica (Thalassiosirales) but with several features uncharacteristic of the genus Lindavia, such as a rimoportula(e) on the valve mantle located on a costa, simple alveolar structure, and spines at the external valve face-mantle junction. A combination of other characters for this species complicate its placement into existing genera, including a lack of central fultoportulae, central area with loculate areolae with domed cribra, and a single ring of mantle fultoportulae with three satellite pores with well-developed cowlings and broad satellite pore covers. Based on this unique set of features, we have established a new genus, Fascinorbis, which appears to represent an important transitional form in the evolution of the Lindavia lineage.

中文翻译：

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Fascinorbis 基因。11 月，来自晚中新世湖相硅藻土的千金藤科 (Bacillariophyta) 新属

我们使用光学和电子显微镜来表征美国爱达荷州 Payette 附近 Chalk Hills 地层中晚中新世淡水硅藻土矿床。该样本中的硅藻组合几乎是单型的，由一个与 Lindavia bodanica (Thalassiosirales) 相似的单一分类群主导，但具有一些与 Lindavia 属不同的特征，例如位于肋骨上的瓣膜上的 rimoportula(e)，简单肺泡结构和外瓣膜面-幔交界处的棘刺。该物种的其他特征的组合使其在现有属中的位置变得复杂，包括缺乏中央 fultoportulae，中央区域具有带圆顶筛的室状乳晕，以及具有三个卫星孔的单环地幔 fultoportulae，具有发达的整流罩和宽阔的卫星毛孔覆盖。