sp. nov. (Diadesmidaceae, Naviculales)-A New Diatom from the Soil of the State Nature Reserve "Bastak" (Jewish Autonomous Region, Russia).

Diatoms inhabit different aquatic and non-aquatic environments, including soils. The naviculoid genus is widespread in various habitats and accounts for 264 species that are only based on morphological and morphometric characteristics. These parameters can greatly vary during the life cycle, making the species very similar to each other and complicating their unambiguous identification. During a study on soil algal diversity in the Russian Far East (Jewish Autonomous Region), we isolated a strain of naviculoid diatom and examined it using an integrative approach (phylogenetic, morphological, ultrastructural data, and life cycle). Phylogenetic analyses, based on chloroplast L gene data, showed affinity of the new strain with the genus . Our alga shares morphological features typical of the genus members but differs from them by having valves with a larger width and hook-shaped external proximal raphe ends deflected to the side opposite the stigma. It was revealed that the strain reproduces via two types of sexual reproduction-isogamy and cis-anisogamy. Based on these phenotypic traits, we described the new isolate as sp. nov.