Revision of European Brachysira species (Brachysiraceae, Bacillariophyta): III. Species formerly included in the Brachysira serians-complex

ABSTRACT

This third paper revising the European Brachysira species deals with Brachysira serians and the closely related B. brebissonii–intermedia complex. The morphology of these species is characterised in greater detail than before based on a combination of analyses of original type material and additional historic and modern samples. All taxa in this complex are typically found in oligotrophic, acidic environments. The largest species in this complex are B. serians and B. wygaschii, which both possess a distinct Voigt discordance. Although they often co-occur, differences in their valve outline and dimensions are distinctive. The type material of Brachysira brebissonii is restudied and differs from a widespread use of this species name in Europe. As a result, Anomoeoneis intermedia, described from Denmark, is considered a more recent heterotypic synonym of B. brebissonii. Two new species are described to clarify the taxonomic identity of the B. brebissonii–intermedia species complex: B. elisabethiana Van de Vijver, C.E.Wetzel & Ector, sp. nov. and B. confusa Van de Vijver, R.L.Albert, B.Kennedy & Kusber, sp. nov. The type material of the morphologically similar B. arctoborealis from North America is studied for comparison. The ecological preferences of all the reported taxa are derived from the accompanying diatom flora in the investigated samples.

KEYWORDS:

• Brachysira
• environmental monitoring
• Europe
• morphology
• taxonomy
• type material

Acknowledgments

Mrs Amelie Jarlman (Lund, Sweden) is thanked for providing recent material from several Swedish rivers and The Canadian Museum of Nature for the loan of type material for B. arctoborealis. We also thank Johanna Albert, Eerika Albrecht and Moritz Albrecht for their help during field work at lake Julma Ölkky.

Disclosure statement

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

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

Funding for this research was partly provided to CEW and LE in the framework of the project DIATOMS (LIST – Luxembourg Institute of Science and Technology).

Notes on contributors

Bart Van de Vijver

Bart Van de Vijver Contribution: generation and analyses of all LM and SEM materials, discussion of results, development, writing, revision and editing of the manuscript.

Tanja M. Schuster

Tanja M. Schuster Contribution: herbarium research, discussion of the results, revision and editing of the manuscript.

Wolf-Henning Kusber

Wolf-Henning Kusber Contribution: advice on taxonomic issues regarding the International Code of Nomenclature for algae, fungi, and plants, discussion of results, revision and editing of the manuscript.

Bryan Kennedy

Brian Kennedy Contribution: taxonomic advice, discussion of results, revision and editing of the manuscript.

Paul B. Hamilton

Raino-Lars Albert Contribution: sampling, discussion of results, revision and editing of the manuscript.

Raino-Lars Albert

Paul B. Hamilton Contribution: discussion of results, revision and editing of the manuscript.

Petra Ballings

Carlos E. Wetzel Contribution: discussion of results, revision and editing of the manuscript.

Carlos E. Wetzel

Luc Ector Contribution: provision of literature, discussion of results, revision and editing of the manuscript.