Orthoseira helvetica sp. nov. – a new diatom (Bacillariophyceae) from the Swiss Alps

Abstract

This paper describes a new diatom species (Orthoseira helvetica sp. nov.) found in the Swiss Alps at an elevation over 2600 m a.s.l. The diatom was recorded at the Macun plateau, Swiss National Park, from samples of terrestrial and wet semi-terrestrial mosses near the stream splash zone. The diatom has a unique set of features and is easily recognized under light and scanning electron microscopy. The most distinctive feature is the presence of a prominent silica collar in a ‘rose flower’ shape rounding each carinoportulae and an additional silica collar on the areolae (first 3–4 rows) bordering the hyaline area. The valve diameter of O. helvetica sp. nov. is 7.5–26.5 µm and possesses 2–3 (usually 3) carinoportulae. Linking spines at the valve face/mantle junction are present, having a simple basis and being triangular in shape.

Keywords:

• Macun lakes
• Swiss National Park
• terrestrial diatoms
• centric diatom
• Mediophyceae
• alpine environments

Acknowledgments

We greatly appreciate the company and assistance of numerous individuals during expeditions. We especially thank C. Jolidon for her continuous support in the field and laboratory. We heartily thank the Swiss National Park (R. Haller, N. Willy) for coordination and logistics over the study period.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The project was partially funded by the Swiss National Park and for sample processing by the program of the Polish Minister of Education and Science named ‘Regional Initiative of Excellence' in the years 2019–2023 (project number 026/RID/2018/19) and 2021 (to ŁP), and by statutory founding of the department of Agroecology and Forest Utilization, University of Rzeszów in 2019 and 2022.