Gomphonema varioreduncum sp. nov., a new species from northern and western Europe and a re-examination of Gomphonema exilissimum

Abstract

Gomphonema parvulum Kützing and morphologically similar species can be difficult to distinguish while differing markedly in their ecology. It is important to identify these species correctly if the ecological status of their habitats is to be assessed accurately. Here, two species in this group are documented using light and scanning electron microscopy. The type material of G. exilissimum (Grunow) Lange-Bertalot & E. Reichardt in the Van Heurck Collection, Meise, was examined, as well as recently collected populations from Scotland and Sweden. A new species, G. varioreduncum Jüttner, Ector, E. Reichardt, Van de Vijver & E.J. Cox which is similar to G. exilissimum and resembles G. cymbelliclinum E. Reichardt & Lange-Bertalot in outline is described and populations from northern and western Europe are illustrated.

Keywords:

• Gomphonema
• new species
• morphology
• oligotrophy
• acidity
• biogeography

Acknowledgements

We would like to thank Anton Igersheim, Natural History Museum Vienna, Austria, for his efforts in finding information about the type material of G. parvulum var. exilissima in the Grunow Collection, Myriam de Haan, National Botanic Garden of Belgium, for taking SEM photos of the type material of G. parvulum var. exilissima, Maria Helena Novais, Centre de Recherche Public – Gabriel Lippmann, Luxembourg, for taking the LM and SEM photos of G. varioreduncum from the Ruisseau de la Celle, and Maurice-Yves Bey, DREAL Rhône-Alpes, France, for the LM photos of G. varioreduncum from the Ruisseau le Liauron, Brian Reynolds and Annie Brittain, Centre for Ecology and Hydrology, Bangor, the Department of Mineralogy, Natural History Museum, London, and the Scottish Environment Protection Agency, Aberdeen, for the chemical analysis. We also thank two reviewers and the editors for their valuable comments which helped to improve the manuscript. The field work in Wales was partly funded by the Welsh Assembly Government and The Wye and Usk Foundation (grant EU Life08 NAT/UK/000201).