Achnanthidium pseudoconspicuum comb. nov.: morphology and ecology of the species and a comparison with related taxa

Abstract

Following the discovery of specimens resembling Achnanthes pseudoconspicua, the type slide of this species was investigated. The latter contained very few valves, which were documented with light microscopy. Specimens from streams and ponds of central and eastern Nepal conformed to the original diagnosis and were investigated using light and electron microscopy. They were compared with similar species around Achnanthes pseudolinearis, Achnanthidium atomus and Achnanthidium pyrenaicum, while Achnanthes pseudoconspicua is transferred to Achnanthidium.

Keywords:

• Achnanthes pseudoconspicua
• Bacillariophyceae
• Himalaya
• Nepal
• Asia

Acknowledgements

We thank Ruth Nielsen, Botanic Garden & Museum, Natural History Museum, University of Copenhagen, for providing the type material of Achnanthes pseudoconspicua; Phil Brewin, Cardiff University, for fieldwork in the Arun catchment; Bishnu Simkhada, Taunton, for field work in the Kathmandu Valley; Roger Wyatt, Jeremy Wilkinson, Alan Jenkins, NERC Centre for Ecology and Hydrology, Wallingford, and Vic Din, Gary Jones, Department of Mineralogy, The Natural History Museum, London, for the water chemistry analyses; Dick Johnson, NERC Centre for Ecology and Hydrology, Wallingford, for organising the trek in 1994; Steve Ormerod, Cardiff University, for providing River Habitat Survey data and Alex Ball and Lauren Howard for support in use of SEM at NHM.