Hidden generic diversity in desmids: description of Pseudomicrasterias gen. nov. (Desmidiaceae, Zygnematophyceae)

ABSTRACT

The taxonomy and nomenclature of Micrasterias arcuata are very problematic because of a wide morphological variation and the large number of poorly circumscribed infraspecific taxa. This study aimed at evaluating the phylogenetic position of strains traditionally assigned to M. arcuata based on molecular and phylogenetic approaches, and morphometric analyses. Multigene analyses were performed using the nuclear SSU rDNA and both chloroplast rbcL and psaA markers. Genetic analyses revealed that all three investigated strains of M. arcuata formed reasonably well-supported lineages, separate from all species of the core Micrasterias lineage and closely related to the Euastrum 2 lineage. Morphometric analyses exhibited differences among strains revealing important trends for morphological differentiation and delimitation of infraspecific taxa assigned to M. arcuata. All three investigated strains are separated by their morphological features and represent different taxonomic entities from the molecular and phylogenetic points of view. Available data support the proposal of Pseudomicrasterias gen. nov. within the family Desmidiaceae. One infraspecific taxon is erected to species level and classified as new combination of Pseudomicrasterias, and two new species are recognized.

KEYWORDS:

• Desmidiales
• Geometric morphometry
• Phylogeny
• Taxonomy

ACKNOWLEDGEMENTS

We thank the director of Reserva Experimental de Itirapina for permission to collect water samples. The authors would like to thank the reviewers and the associate editor of the journal for their constructive critique and recommendations that improved the manuscript.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.

SUPPLEMENTARY MATERIAL

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Additional information

Funding

This work was supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES Brazilian Agency, Finance code 001) for the PhD fellowship and the fellowship (Process N° 88881.189622/2018-1) granted in the Doctoral Sandwich Program (CBA); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, Processes 2016/07089-5 and 2019/03177-5) for scholarship, financial and scientific support granted (TGS). This work was also supported by the Institutional Funds of the Charles University in Prague (PŠ).