Tillmann Urban, Gottschling Marc, Wietkamp Stephan, Hoppenrath Mona
Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany.
Department Biologie-Systematik, Biodiversität & Evolution der Pflanzen, GeoBio-Center, Ludwig-Maximilians-Universität München, Menzinger Str. 67, 80638 München, Germany.
Microorganisms. 2023 Jan 20;11(2):271. doi: 10.3390/microorganisms11020271.
comprises dinophytes with several unique traits, including the presence of two large thecal plates and apical insertion of flagella. Species delimitation for many small and similar planktonic species is challenging, as SEM analyses and DNA sequence information of type material are rarely available. Based on a strain from the North Atlantic sp. nov. is described here. Cells were small (9.0-12.8 µm long, 8.5-11.9 µm deep), oval to almost round in lateral view and moderately compressed. The ovoid nucleus was in median or slightly sub-median position on the cells ventral side. The plate surface appeared spiny in light microscopy with thecal pores visible in empty thecae. Electron microscopy revealed plates densely covered by relatively long spines and two size classes of thecal pores. The periflagellar area consisted of 8 platelets, and there was a prominent wing (ca. 1 µm wide and long) on platelet 1. The new species is distinct in DNA trees and embedded in the species group. It differs from the protologues of other small species of by the unique combination of cell size and shape, the presence of long spines on the thecal plate surface and scattered thecal pores. The thorough morphological description of this species, representing a previously uncharacterised lineage within increases and improves our knowledge of the diversity within this important group of planktonic organisms.
包括具有几个独特特征的甲藻，包括存在两个大型壳板和鞭毛的顶端插入。对许多小型且相似的浮游物种进行物种界定具有挑战性，因为很少能获得模式标本的扫描电子显微镜分析和DNA序列信息。基于来自北大西洋的一个菌株，这里描述了一个新物种。细胞很小（长9.0 - 12.8微米，深8.5 - 11.9微米），侧面观呈椭圆形至近圆形，且适度压缩。卵形细胞核位于细胞腹侧的中部或稍偏中部位置。在光学显微镜下，板表面看起来有刺，在空壳中可见壳孔。电子显微镜显示板上密集覆盖着相对较长的刺和两种大小类别的壳孔。鞭毛周围区域由8个小板组成，在小板1上有一个突出翼（约1微米宽和长）。这个新物种在DNA树中是独特的，并嵌入该物种组中。它与其他小型物种的原始描述不同，具有细胞大小和形状的独特组合、壳板表面存在长刺以及分散的壳孔。对该物种的全面形态学描述，代表了一个以前未被描述的谱系，增加并改善了我们对这一重要浮游生物群体多样性的认识。
