Reinvestigation of African Surirella taxa (Bacillariophyta) described by B.J. Cholnoky with some remarks on digitization of diatom types

Abstract

Cholnoky described several new Surirella taxa from Africa and we have re-investigated this material. As many other of his contemporary authors, especially in the case of description of new African diatoms, Cholnoky did not indicate holotypes. In the present paper original materials are re-evaluated, lectotypes and a holotype are designated and also epitypes whenever it was appropriate. Taxa later transferred to Stenopterobia have not been taken into account. A short description of the seven species concerned (Surirella anassae, S. chasei, S. coei, S. oliffii, S. ostentata = Surirella ovata var. africana, S. pseudotenuis and S. pseudothienemannii) is given based on the original light microscopic descriptions. Additional morphological information based on scanning electron microscopy is added if available. The presently known ecology and distribution of the taxa is given as are other remarks, based on own observations. For each of the seven taxa Cholnoky's original drawings are presented, which were later re-drawn for publication and which are kept in the archive of the South African National Diatom Collection. The results are discussed referring to the outcome of the digitization project of African Surirellaceae (diatoms, microscopic algae) in the frame of the African Plants Initiative