Analysis of the type material of Achnanthes hauckiana Grunow (Achnanthaceae, Bacillariophyceae)

ABSTRACT

The type material of Achnanthes hauckiana Grunow has been investigated using light and scanning electron microscopy. The species, transferred to the genus Planothidium, was frequently reported from brackish and even marine environments. The original Grunow material was collected from a karstic spring near Trieste. Analysis of the material and of samples collected from the Croatian Krka River, resulted in a better understanding of the morphology of Planothidium hauckianum and a better characterization of the diatom flora of which it is a dominant component. The paper compares the species with similar Planothidium species from the P. delicatulum complex and revises published images of P. hauckianum in literature, making it clear that all reported and illustrated brackish populations of P. hauckianum belong to different, often unknown species. The presence of Planothidium hauckianum is limited to karstic spring areas, most likely showing a very restricted biogeographical distribution.

KEYWORDS:

• Planothidium
• ecology
• type material
• Croatia
• morphology

Author contributions

Antonija Kulaš: sampling materials at Krka spring, contributed in description of study area, writing, revision and editing of the manuscript.

Marija Gligora Udovič: project development, contributing to the main conceptual ideas and implementation of the research of diatoms of Krka River; analysis of the environmental results, revision and editing of the manuscript.

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

Bart Van de Vijver: analysis of the Achnanthes hauckiana type material from the Grunow collection (Naturhistorisches Museum Wien, Austria), discussion of results, development, writing, revision and editing of the manuscript.

Acknowledgments

Mrs Myriam de Haan is thanked for her help with the scanning electron microscopy. Dr Anton Igersheim (Grunow collection, Naturhistorisches Museum Wien, Austria) is acknowledged for sending the type material of Achnanthes hauckiana. Dr Zlatko Levkov is thanked for his help with identifying the diatom flora of the type material and Krka Spring. The authors would like to thank mr. sc. Gordana Goreta for her enthusiasm and support in survey of the diatoms of the Krka River.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This survey is financially supported by the National Park Krka. Funding for this research was also provided in the framework of the project DIATOMS (LIST – Luxembourg Institute of Science and Technology).