DNA barcoding reveals a new species of Stephanodiscus Ehrenberg

Abstract

The taxonomic situation of the species complex around Stephanodiscus minutulus/parvus is controversial. Insufficient species description and fossil type material contribute to persistent confusion. Håkansson & Kling (1990) described S. binatus as another morphologically similar species in this group. Following the reinvestigation of the type materials of S. minutulus and S. parvus by Houk et al. (2014), it seems that these names are often falsely applied to S. binatus. Monoclonal strains of the S. minutulus/parvus/binatus species complex from European water bodies were established for morphological and molecular analyses. Most of the strains belonged to S. binatus, which seems to be very common in meso- to eutrophic waters in middle Europe. Differing in the barcoding markers, the remaining strains represented a new species, S. neglectus sp. nov., morphologically similar to S. binatus. Stephanodiscus minutulus and S. parvus were not found. Seven strains of S. neglectus sp. nov., seven strains of S. binatus and two strains of Cyclostephanos invisitatus were subjected to detailed morphometric investigation. Four strains of Stephanodiscus hantzschii, Stephanodiscus neoastrea, Cyclostephanos dubius were also included in the molecular analysis. The morphological differential diagnosis of S. neglectus sp. nov. from S. binatus is difficult, but the molecular results show that the species are distinctly different. Using three different loci the distance between the new species and S. binatus equals the distance between S. binatus and S. hantzschii.

Keywords:

• Stephanodiscus neglectus sp. nov.
• Stephanodiscus minutulus/parvus/binatus complex
• DNA barcoding
• morphometric analysis

Acknowledgements

We would like to thank Karin Fink, Steffi Gottschalk and Petra Werner for their sampling efforts.

Disclosure statement

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

Supplemental data

Supplemental data for this article can be accessed here https://do.org/10.1080/0269249X.2022.2078427.

Additional information

Funding

This research was funded by the State Postgraduate Scholarship Program of the State of Mecklenburg-Vorpommern.