Aulacoseira capitalina sp. nov. (Bacillariophyta) from the Middle Miocene sediments of the Barguzin Valley, Baikal Rift Zone (Russia)

• Main Authors: Titova, Lybov', Hassan, Abdulmonem, Usoltseva, Marina
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2022
• Subjects: Aulacoseira capitalina; elliptical valves; fossil diatoms; Middle Miocene; Titova; Sibirica
• Online Access: https://zenodo.org/record/7726461; https://doi.org/10.5281/zenodo.7726461

Using light and scanning electron microscopy, a new species Aulacoseira capitalina Titova et Usoltseva from the Middle Miocene deposits of the Barguzin Valley is described. It is shown that the new species is similar to other elliptical species in terms of elliptical valve face profile, diameter, deep ringleist, but differs in the shape of separating spines, the absence of ridge structure and the shape of rimoportulae. The finding of A. capitalina in the Middle Miocene deposits of the Barguzin Valley expands the range of distribution of elliptical species. The authors are grateful to S.V. Rasskazov (Institute of the Earth's Crust SB RAS) for organizing of the expedition and for taking samples from the cores of the Barguzin Valley. We thank the director of Central Siberian Botanical Garden (Novosibirsk, Russia) Viсtor Chepinoga for the opportunity to place the type specimen in the collection. The work is done within the State Assignments of Limnological Institute (0279–2021–0008). Microscopic studies were carried out in the Electron microscopy center of collective instrumental center "Ultramicroanalysis" Limnological Institute of the Siberian Branch of the Russian Academy of Sciences