Kamakura Shiho, Yamada Kazumasa, Arguelles Eldrin D L R, Kuwata Akira, Nagumo Tamotsu, Takahashi Masakazu, Sawada Ken, Ichinomiya Mutsuo, Sato Shinya
KYOUSEI Science Center for Life and Nature, Nara Women's University, Nara, Japan.
Faculty of Marine Science and Technology, Fukui Prefectural University, Fukui, Japan.
J Phycol. 2025 Aug;61(4):757-776. doi: 10.1111/jpy.70043. Epub 2025 Jun 19.
The class Bolidophyceae, which consists of small phytoplankton distributed worldwide, is the sister group of diatoms. This class has contained only one order, the Parmales, until now. In this study, we established a new order Lepidoparmales Kamakura & S.Sato ord. nov. and a new family Lepidoparmaceae Kamakura & S.Sato fam. nov., within the Bolidophyceae, and described Lepidoparma frigida Kamakura & S.Sato gen. et sp. nov. from the Sea of Okhotsk. We conducted a comprehensive comparison of L. frigida with diatoms and other parmaleans through analysis of its molecular phylogeny, morphology, ultrastructure, ontogeny, distribution, and lipid composition. The cell surface of L. frigida is covered with numerous siliceous scales with radial patterns similar to centric diatom valves; this character distinguishes it from other known parmaleans. Intriguingly, its appearance resembles the hypothesized "pre-diatom," which was proposed to be a precursor to primitive diatoms. The discovery and characterization of L. frigida will provide valuable insights into the evolutionary processes of both diatoms and bolidophytes and shed light on their common ancestor.
波粒藻纲由分布于全球的小型浮游植物组成，是硅藻的姐妹类群。到目前为止，该纲仅包含一个目，即帕马目。在本研究中，我们在波粒藻纲内建立了一个新目——镰鳞帕马目镰仓 & S. 佐藤目，新科——镰鳞帕马科镰仓 & S. 佐藤科，并描述了鄂霍次克海的新属新种——冷镰鳞藻镰仓 & S. 佐藤。我们通过分析其分子系统发育、形态学、超微结构、个体发育、分布和脂质组成，对冷镰鳞藻与硅藻及其他帕马目藻类进行了全面比较。冷镰鳞藻的细胞表面覆盖着许多具有放射状图案的硅质鳞片，类似于中心硅藻的壳面；这一特征使其有别于其他已知的帕马目藻类。有趣的是，它的外观类似于假设的“前硅藻”，后者被认为是原始硅藻的前身。冷镰鳞藻的发现和特征描述将为硅藻和波粒藻的进化过程提供有价值的见解，并揭示它们的共同祖先。
