Rediscovery of the Ochromonas type species Ochromonas triangulata (Chrysophyceae) from its type locality (Lake Veysove, Donetsk region, Ukraine)

Abstract:

Ochromonas triangulata, the type species for a genus with over 125 taxa, was collected for only the second time, again from the type locality. Cell morphology, cell division, palmelloid stage and cyst structure generally agreed with the original description. Molecular phylogenetic analysis based on the 18S rRNA gene revealed 13 clades of Ochromonas-like flagellates as well as the clade represented by our O. triangulata strain and the nearly identical strain RCC-21/AC025. We also conducted a concatenated analysis using the 18S rRNA and the rbcL genes, and we recovered the same 14 clades. One clade, containing strains CCAP 933/27 and CCMP1861, previously named Ochromonas tuberculata, was re-identified as Chrysastrella paradoxa and Chrysastrella breviappendiculata, respectively. One clade included the Poterioochromonas strains but we were unable to convincingly connect species names to the strains because authentic strains were unknown or not examined. Organisms in the clade that included the well-known Ochromonas danica were assigned to Chlorochromonas. The generic name Melkoniania gen. nov. was proposed for one distinct clade of marine flagellates. These changes addressed some of the issues associated with the polyphyletic Ochromonas sensu lato but many problems remained.

Key Words::

• Chlorochromonas
• Chrysastrella
• Chrysophyceae
• Melkoniania
• Nomenclature
• Ochromonas triangulata
• Phylogeny
• Poterioochromonas

ACKNOWLEDGEMENTS

We thank Prof. Dr. Michael Melkonian for generously helping with critical translations of German text, we thank Prof. Dr. Jens Boenigk for assistance with colourless chrysophyte nomenclature and we thank the two reviewers for their corrections and contributions. We thank the National Center for Marine Algae and Microbiota for providing some cultures. We thank Dr. Rebecca Gast for providing additional information about a GenBank accession from Antarctica. This study was supported by the Collaborative Genome Program (20140428) funded by Ministry of Oceans and Fisheries of Korea, the grant (NRF-2017R1A2B3001923) from the National Research Foundation of Korea (NRF) and the Next-generation BioGreen21 program (PJ011121) of Rural Development Administration of Korea to HSY. This study searching for the type species began long ago with NSF grant 9419498 to RAA.

SUPPLEMENTARY DATA

Supplementary data associated with this article can be found online at http://dx.doi.org/10.2216/17-15.1.s1.