ABSTRACT
Cocconeis Ehrenberg is a monoraphid diatom genus included in the Family Cocconeidaceae. It occurs in marine and freshwater environments, living attached to a substrate by the raphid valve. Through the documentation of the taxa found in LM and SEM analyses, this study aims to increase the knowledge about freshwater Cocconeis species occurring in Brazilian waters. In addition, one new species is formally described here. Seven samples were chosen from a total of 346 samples investigated for monoraphid diatoms in São Paulo state, Brazil, due to their representativeness for Cocconeis biodiversity. These samples include periphytic, metaphytic and surface sediment materials. One sample from Ivory Coast was also analysed to compare a similar taxon with the taxa found. The biodiversity and the occurrence of the genus Cocconeis were low in our study material (nine taxa) despite the great amount of samples analysed for monoraphid taxa. Nevertheless, one taxon was considered a new species, being described here. Finally, this study was based on morphological characters of the frustule observed in LM and SEM analysis, showing the importance of both to better understand the variability of each species and to separate similar taxa.
Acknowledgments
The authors are grateful to M. Potapova (Drexel University, Philadelphia, PA, USA) for for providing the holotype images and original drawings of C. fluviatilis and C. schroederi.
Disclosure statement
No potential conflict of interest was reported by the authors.
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Notes on contributors
Lívia F. Costa
Lívia F. Costa PhD student in plant biodiversity and the environment at the Botanic Institute of São Paulo. She has written five scientific articles, including co-authorships and one volume of Bibliotheca Diatomologica, all of them related to diatom taxonomy and ecology from Brazilian environments. Contribution: preparation of images, bibliographic research, writing and editing of the manuscript.
Carlos E. Wetzel
Carlos E. Wetzel Botanist and researcher at the Luxembourg Institute of Science and Technology (LIST) has written over 100 scientific articles related to diatoms. He has been working on diatoms in rivers, lakes and soils, worldwide. Carlos E. Wetzel has been running numerous training courses on diatom ecology and taxonomy designed for biologists, technicians and ecologists, contributing to the continuous improvement in the Water Framework Directive implementation in Europe. Contribution: scanning electron microscopy, bibliographic research, revision and editing of the manuscript.
Luc Ector
Luc Ector Botanist and senior researcher at the Luxembourg Institute of Science and Technology. He has written over 210 articles and has been working on diatoms in rivers, lakes and soils for the last 30 years. He was the President of the “Association des Diatomistes de Langue Française (ADLaF)”, which organizes annual meetings on diatom taxonomy, ecology and related subjects. Over the last 20 years, he has been organizing and teaching numerous training courses on diatom ecology and taxonomy designed for biologists, technicians and ecologists, contributing to the continuous improvement in the Water Framework Directive implementation in Europe. Contribution: discussion of results, bibliographic research, revision and editing of the manuscript.
Denise C. Bicudo
Denise C. Bicudo Botanist and researcher at the Botanic Institute of São Paulo. She has written over 80 articles, 30 books and chapters, and has been working on limnology, paleolimnology and diatom ecology for the last decades. She has been leading masters and PhD students for 20 years, including the first author of this study. Contribution: discussion of results, bibliographic research, revision and editing of the manuscript.