1. Department of Environmental and Plant Biology, Ohio University, Athens, Ohio 45701, USA
2. Unit for Environmental Science and Management, North-West University, Potchefstroom, 2520, South Africa
3. South African National Diatom Collection, South African Institute for Aquatic Biodiversity (SAIAB), Makhanda, 6140, South Africa
4. Faculty of Science, Department of Botany, University of Lagos, Akoka 23010, Nigeria