Fottea

Fottea 2022, 22(2):181-191 | DOI: 10.5507/fot.2021.025

Resurrection of the diatom genus Stephanocyclus (Coscinodiscophyceae: Stephanodiscaceae) on the basis of an integrated molecular and morphological approach

Maxim Kulikovskiy^1*, Sergei Genkal², Yevhen Maltsev¹, Anton Glushchenko¹, Irina Kuznetsova¹, Dmitry Kapustin¹, Evgeniy Gusev¹, Nikita Martynenko¹, John Patrick Kociolek^{3, 4}

¹ К.А. Timiryazev Institute of Plant Physiology RAS, IPP RAS, 127276 Moscow, Russia;

^* Corresponding author: max-kulikovsky@yandex.ru

² Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, 152742 Yaroslavl, Nekouz, Borok, Russia

³ Museum of Natural History and

⁴ Department of Ecology and Evolutionary Biology University of Colorado, 80309, Boulder, Colorado, USA

The history of the description and subsequent consideration of the diatom genus Stephanocyclus Skabitschevsky (Thalassiosirales, Bacillariophyta) is discussed. The new genus was described on the basis of a new species, S. planum Skabitschevsky, originally collected from the River Ob. However, the genus has been more or less forgotten since its initial description in 1975. Type material from Skabitschevsky's collection has subsequently been lost. An epitype for this species is recognized from the same region as the original collection, and typified with a population from Lake Baikal and using molecular data. The population from Lake Baikal fully corresponds in terms of morphological features with the population originally investigated by Skabitschevsky. Morphology of the genus Stephanocyclus is discussed and, on the basis of an integrated molecular and morphological investigation, we propose to recognize the genus, including four species within it. Three taxa are transferred to the genus, including Cyclotella cryptica, C. gamma and C. meneghiniana. A comparison of Stephanocyclus with other cyclotelloid genera is given.

Keywords: diatoms, Cyclotella, Stephanocyclus, molecular investigation, morphology, taxonomy

Received: April 26, 2021; Revised: December 8, 2021; Accepted: December 17, 2021; Prepublished online: August 26, 2022; Published: October 31, 2022  Show citation