Department of Oceanography, College of Ocean Science & Technology, Kunsan National University, Gunsan, 54150, Republic of Korea.
Institute of Marine and Environmental Sciences, and Natural Sciences Research and Educational Centre, University of Szczecin, Mickiewicza 16a, PL 70-383, Szczecin, Poland.
J Phycol. 2020 Aug;56(4):953-978. doi: 10.1111/jpy.12998. Epub 2020 Apr 23.
Detailed morphological documentation is provided for established Proschkinia taxa, including the generitype, P. bulnheimii, and P. complanata, P. complanatula, P. complanatoides and P. hyalosirella, and six new species. All established taxa are characterized from original material from historical collections. The new species described in this paper (P. luticola, P. staurospeciosa, P. impar, P. modesta, P. fistulispectabilis, and P. rosowskii) were isolated from the Western Pacific (Yellow Sea coast of Korea) and the Atlantic (Scottish and Texas coasts). Thorough documentation of the frustule, valve and protoplast architecture revealed the combination of characters diagnostic of the genus Proschkinia: a single-lobed chloroplast; a broad girdle composed of U-shaped, perforated bands; the position of the conopeate raphe-sternum relative to the external and internal valve surface; and the presence of an occluded process through the valve, termed the "fistula". Seven strains of Proschkinia were grown in culture and five of these were sequenced for nuclear ribosomal SSU and plastid-encoded rbcL. Phylogenetic analysis recovered a clade of Proschkinia with Fistulifera, another fistula-bearing diatom genus, and together these were sister to a clade formed of the Stauroneidaceae; in turn, all of these were sister to a clade composed of Parlibellus and two monoraphid genera Astartiella and Schizostauron. Despite morphological similarities between Proschkinia and the Naviculaceae, these two taxa are distant in our analysis. We document the variation in the morphology of Proschkinia, including significant variability in the fistula, suggesting that fistula ultrastructure might be one of the key features for species identification within the genus.
为已建立的 Proschkinia 分类群提供了详细的形态学描述，包括模式种 P. bulnheimii 和 P. complanata、P. complanatula、P. complanatoides 和 P. hyalosirella，以及六个新种。所有已建立的分类群均基于历史标本进行描述。本文描述的新种（P. luticola、P. staurospeciosa、P. impar、P. modesta、P. fistulispectabilis 和 P. rosowskii）是从西太平洋（韩国黄海海岸）和大西洋（苏格兰和德克萨斯海岸）分离出来的。对壳面、壳缝和原生质体结构的详细描述揭示了 Proschkinia 属的特征组合：单个叶状叶绿体；由 U 形、穿孔带组成的宽环带；刺丝列孔位于外部和内部壳面的相对位置；以及通过壳面的闭塞过程，称为“瘘管”。Proschkinia 的 7 个菌株在培养中生长，其中 5 个菌株的核核糖体 SSU 和质体编码 rbcL 进行了测序。系统发育分析重建了一个包含 Fistulifera（另一种具瘘管的硅藻属）的 Proschkinia 分支，与 Stauroneidaceae 形成姐妹分支；反过来，这些分支与由 Parlibellus 和两个单壳缝属 Astartiella 和 Schizostauron 组成的分支形成姐妹分支。尽管 Proschkinia 和 Naviculaceae 之间存在形态相似性，但在我们的分析中，这两个分类群相距很远。我们记录了 Proschkinia 形态的变化，包括瘘管的显著变化，这表明瘘管的超微结构可能是该属种间鉴定的关键特征之一。
