Surirella capensis Ehrenberg ex Cocquyt et R. Jahn sp. nov., a rare and historical diatom species from South Africa

The rare and probably endemic diatom Surirella capensis is described and its type designated in slides made by Ehrenberg in 1843 from material collected in South Africa. The type specimen and further specimens found in Ehrenberg’s historical material are illustrated with the light microscope. Ehrenberg had named this taxon S. capensis, but had never published a picture or a diagnosis. The distinction between S. capensis and the closely related S. sparsipunctata, a diatom known from Central Africa, is discussed.