Freshwater diatoms in the Democratic Republic of the Congo: a historical overview of the research and publications

An overview of the diatom research in the DR Congo is given based on literature data starting in 1938 with the work of Zanon and excluding the East African Lakes as these were already discussed in previous papers. For each literature record the diatom genera mentioned are presented as well as all diatom taxa described from the Congo as new. In total, 106 new taxa were documented, of which Nitzschia with 40 taxa is far the most important genus followed by Navicula s.l. and Pinnularia and with 15 and 13 taxa respectively. Particular attention was paid to the local research of students found in unpublished theses at bachelor, licentiate, master and PhD level. Diatom records in these works are almost all restricted to genus level, although in the last decade an attempt to delimit species can be observed. This accompanies the renewed taxonomic interest in the Congo basin during the last decade. Renewed taxonomic interest can also be seen in the genera: the first period being situated during the lumping period, while more recent works follow the current taxonomic classification, for example Navicula s.l. versus Navicula, Cavinula, Craticula, Diadesmis, Geissleria, Humidophila, Luticola, etc.