Reassessment of pore occlusion in some diatom taxa with re-evaluation of Mereschkowsky (Bacillariophyceae: Cymbellales) and description of two new genera.

In this article, the history and taxonomy of , the type species of the genus , was discussed. We investigated the structure of pore occlusions in and related genera. As a result, we propose a new classification for tectulum-like types of pore occlusions. The new classification is congruent with previously-published and newly-constructed phylogenies based on molecular data. Based on the different structures of the pore occlusions, species of are transferred to gen. nov. Hence, 168 new combinations are introduced. A new diatom species, with a similar morphology to , was discovered in Bắc Kạn Province, Vietnam. It is described in this article as sp. nov. is transferred to gen. nov. We also illustrate herein and compare it to sp. nov. An unknown diatom, similar to , was discovered in Chukotka, Russia. It is introduced as sp. nov. below. Additionally, we discuss the distribution of some species of gen. nov. and gen. nov.