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Otto Müller's published data and pictures of Navicula elkab were re-evaluated and compared with literature data and a Holocene sediment core material from Ounianga (Chad, Africa). A valid name under Craticula is provided and a lectotype and an epitype are selected. An unusual siliceous covering over the valves is discussed
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Type microscope slides and material from Ghana from which Foged described nine new Surirella taxa in the 1960's were reinvestigated. Although these taxa have not been reported in the literature afterwards, the results of our study confirm the identity of six species: Surirella agonaensis, S. bonsaensis, S. examangensis, S. nagbogensis, S. sorriensis and S. takoradiensis. They constitute an important element of the endemic diatom flora of West Africa. The study of Surirella takoradiensis var. suhinensis resulted in its proposed synonymy with the nominate variety. Surirella delicatissima var. ghanaensis is transferred to the genus Stenopterobia: Stenopterobia delicatissima var. ghanaensis (Foged) Cocquyt & Lisner comb. nov. Valves resembling Foged's drawing of Surirella dodowaensis could not be detected on the holotype slide; however, two observed frustules in girdle view are in agreement with the description of this taxon.
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ALG Algae --- symposium programmes --- Central Europe --- Bacillariophyta = Diatoms = Diatomeae
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At the beginning of the 20th century, Otto Müller described over 100 new East African diatom taxa from algae samples, taken during the German "Nyassa-See- und Kinga-Gebirgs-Expedition". He published valuable drawings and wrote detailed descriptions, however, in German and in a journal which is not well accessible today. Later authors, however, regarded these early African taxa often as synonyms or as infraspecific taxa of European species. The renewed attention that is given in the last two decades to the diatom flora of East Africa makes it evident that Müller's taxa have to be reinvestigated, including light as well as scanning electron microscopy, in order to evaluate possible new or endemic species. This was recently done for his Surirella taxa, a typical component of the African Great Lakes diatom flora of which many species are endemic to this area. The study of permanent LM slides as well as original materials allowed us not only to choose lectotypes, respectively epitypes, but also to study valve variability, while detailed information on valve ultrastructure was acquired by SEM investigation. Additional data, originating from materials of later periods in the same region (e.g. Lakes Tanganyika, Malawi, Victoria, Edward), was incorporated in the investigation to study the variability in valve morphology and the African distribution of each species. Otto Müller's samples thus provide the means to study historical African diatom diversity which can be used as a baseline for modern biodiversity assessment. Moreover, to make this information available worldwide, type information and English description of each taxon are published in international journals and on the AlgaTerra Information System [www.algaterra.org] which has been developed and is kept updated by the Botanic Garden and Botanical Museum Berlin-Dahlem (BGBM). High resolution digital photographs will also be available in the future on the API website [www.aluka.org]
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Beiträge vom 24. Treffen Deutschsprachiger Diatomologen mit Internationaler Beteilung
ALG Algae --- symposium abstracts --- Central Europe --- Bacillariophyta = Diatoms = Diatomeae
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ALG Algae --- symposium proceedings --- Central Europe --- Bacillariophyta = Diatoms = Diatomeae
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