Larsson Michaela E, Hallegraeff Gustaaf, Doblin Martina A, Tillmann Urban
Department of Water and Environmental Regulation, Aquatic Science Branch, Joondalup, Western Australia, Australia.
Climate Change Cluster (C3), University of Technology Sydney, Broadway, New South Wales, Australia.
J Eukaryot Microbiol. 2025 Jul-Aug;72(4):e70017. doi: 10.1111/jeu.70017.
Prorocentrum cf. balticum was the provisional designation assigned to strains of a small, pelagic, mixoplanktonic dinoflagellate found to produce carbon-rich mucilage-based prey capture devices, termed "mucospheres." Here we characterize the morphology and phylogeny of the strains, describe them as Prorocentrum insidiosum sp. nov., and discuss common morphological features among the six species of the phylogenetically defined P. cordatum group. Cells of P. insidiosum sp. nov. were round to slightly ovate in lateral view, 12-16 μm long and 8-15 μm deep, and laterally compressed. Scanning electron microscopy revealed the thecal plates were densely ornamented with short spines and there were two size classes of pores irregularly distributed across both plates, and a row of two to four large round pores in apical-ventral position on the right thecal plate. The periflagellar area consisted of eight platelets, and there were two prominent wing-like apical projections in the form of a double layered curved structure on platelet 1 with additional projections on most other platelets except platelet 4. Prorocentrum insidiosum sp. nov. is distinct from all genetically represented species within the genus and possesses a unique combination of morphological features differentiating it from other protologues of small Prorocentrum species.
波罗的海原甲藻（Prorocentrum cf. balticum）是对一种小型、浮游、混合浮游性甲藻菌株的临时命名，该菌株被发现能产生富含碳的、基于黏液的猎物捕获装置，称为“黏液球”。在此，我们对这些菌株的形态和系统发育进行了表征，将它们描述为隐匿原甲藻（Prorocentrum insidiosum）新种，并讨论了系统发育定义的心形原甲藻（P. cordatum）组六种物种之间的共同形态特征。隐匿原甲藻新种的细胞在侧视图中呈圆形至略卵形，长12 - 16μm，深8 - 15μm，且侧向压缩。扫描电子显微镜显示，壳板上密布着短刺，两块板上均不规则分布着两种大小的孔，右侧壳板的顶腹位置有一排两到四个大的圆形孔。鞭毛周区域由八个小板组成，在第1块小板上有两个突出的翼状顶端突起，呈双层弯曲结构，除第4块小板外，大多数其他小板上还有额外的突起。隐匿原甲藻新种与该属内所有已进行基因表征的物种不同，具有独特的形态特征组合，使其与小型原甲藻物种的其他原始描述有所区别。
