Revision of European Brachysira species (Brachysiraceae, Bacillariophyta): II. The Brachysira styriaca and B. zellensis group

ABSTRACT

This second paper on the revision of the taxonomic identity of several Brachysira species in Europe deals with Brachysira styriaca (Grunow) R.Ross and B. zellensis (Grunow) Round & D.G.Mann. Both species were described by Grunow based on material from Lake Erlauf (Lower Austria and Styria, Austria). Analysis of type material, additional historic and modern samples showed that most populations of B. styriaca from northern Europe belong to a different taxon. This was already described 70 years ago by Cleve-Euler as Anomoeoneis decipiens A.Cleve and is newly recombined here as Brachysira decipiens (A.Cleve) Van de Vijver & Kusber comb. nov. Brachysira decipiens and B. styriaca can be differentiated based on several morphological and distinct ecological preferences. Brachysira styriaca is typically found in calcium-bicarbonate, oligotrophic, alkaline lakes, whereas B. decipiens prefers acid environments. Brachysira rylandsiana Van de Vijver, D.M.Williams & Ector, sp. nov. is split from Brachysira zellensis based on the parallel valve margins, cuneately rounded apices, and several smaller, ultrastructural details. All species are illustrated with both LM and SEM observations. Their ecological preferences are derived from the accompanying diatom flora in the different investigated samples and the literature.

KEYWORDS:

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

Acknowledgments

Dr Gabriele Hofmann (Glashütten, Germany) is thanked for sending us material of sample S-292. Mrs Petra Ballings is thanked for her help with the SEM observations.

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

No funding was obtained for this project.

Notes on contributors

Bart Van de Vijver

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

Tanja M. Schuster

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

Wolf-Henning Kusber

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

David M. Williams

David M. Williams discussion of results, revision and editing of the manuscript.

Carlos E. Wetzel

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

Luc Ector

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