The identity of Gomphonema clavatum Ehrenberg (Bacillariophyceae) and typification of five species of the genus Gomphonema described by C.G. Ehrenberg

Abstract

This paper reports on investigations of original material of C.G. Ehrenberg housed in the Museum für Naturkunde, Berlin (BHUPM). The type material of eight Gomphonema species described by Ehrenberg was studied. The following species are lectotypified: G. clavatum Ehrenberg, G. longiceps Ehrenberg, G. longicolle Ehrenberg, G. mustela Ehrenberg and G. rhombeum Ehrenberg. The holotype of G. tenuicolle Ehrenberg is illustrated. In addition, the original material of G. leibleinii Agardh, housed in the Museum of Natural History, Vienna, was studied. The most important results are: G. clavatum and G. leibleinii are determined to be conspecific with G. olivaceum (Hornemann) Brébisson, G. longiceps is the correct name of G. clavatum sensu Krammer & Lange-Bertalot (1986.) pro parte, and G. mustela represents a (post) initial valve of G. coronatum Ehrenberg. Some of the problems and difficulties that may arise when working on Ehrenberg's material or types are discussed with special reference to G. americanum and G. turris.

Keywords:

• diatoms
• Gomphonema clavatum
• Ehrenberg
• lectotype
• taxonomy

Acknowledgements

The author would like to thank Dr David Lazarus for his supremely generous help during my visits at the Ehrenberg collection. Special thanks to Dr Regine Jahn for SEM micrographs of diatoms from Ehrenberg's material from West Point, New York, to anonymous reviewers for corrections of the language and last but not least to Prof. Dr Dr h.c. mult. Horst Lange-Bertalot for advice and information at any time.