Morphological variability in Alveolophora areolata (Moisseeva) Moisseeva and Alveolophora bifaria Nevretdinova & Moisseeva

Abstract

The morphological variability of two biostratigraphically important diatom species of the Russian Far East, Alveolophora areolata (Moisseeva) Moisseeva and Alveolophora bifaria Nevretdinova et Moisseeva,was studied using light and scanning electron microscopy. High variability was found in mantle height, diameter, stria organization, areola location on the valve face, alveolus structure and costae of A. bifaria, but less variability in A. areolata. Separation valves of A. areolata lack spines, and rimoportulae were found on the valve face for the first time. Based on the new morphological data, descriptions for these taxa have been emended.

Keywords:

• Alveolophora areolata
• Alveolophora bifaria
• Miocene deposits
• morphological variability
• fine structure
• alveoli
• costae
• rimoportulae
• ringleiste

Acknowledgements

We would like to thank Dr Galina Khursevich for giving us the material, Dr Yelena Likhoshway, Dr Galina Khursevich, Dr David Jewson and two anonymous reviewers for commenting on, and improving the paper. We thank Mr Victor Egorov for his assistance during the work on the SEM.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by project № 0345–2019–0001 in the Electron Microscopy Center of Collective Instrumental Center ‘Ultra microanalysis’ at the Limnological Institute of the Siberian Branch of the Russian Academy of Sciences.