Fottea 8, Number 1
REVIEW
KOMÁREK, J & ZAPOMĚLOVÁ, E.: Planktic morphospecies of the cyanobacterial genus Anabaena = subg. Dolichospermum – 2. part: straight types. - Fottea 8(1): 1–14, 2008
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MANN, D.G., THOMAS, S.J. & EVANS, K.M.: Revision of the diatom genus Sellaphora: a first account of the larger species in the British Isles. - Fottea 8(1): 15–78, 2008
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REGULAR ARTICLE
KOMÁREK, J.: The cyanobacterial genus Macrospermum. - Fottea 8(1): 79-86, 2008
Abstract | PDF
KOMÁREK, J. & ZAPOMĚLOVÁ, E.: Planktic morphospecies of the cyanobacterial genus Anabaena = subg. Dolichospermum – 2. part: straight types.
This small tropical cyanobacterial group, containing Anabaena volzii Lemmermann and a few related species (A. fuellebornii SCHMIDLE, A. unispora GARDNER, A. mysorensis GONZALVES & KAMAT), differs substantially phenotypically from all other planktic or benthic Anabaena types, mainly by the subsymmetric structure of the trichomes, type of akinete formation and restricted ecology. The taxonomic uniformity of all other Anabaenalike clusters (typical benthic Anabaena, planktic Anabaena subg. Dolichospermum, Trichormus, Aphanizomenon, Cuspidothrix) was already supported by molecular analyses. All of them also have their typical morphological markers, which are clearly different from the “Anabaena volzii – cluster”. Therefore, this group can not be classified in any of the mentioned revised genera and must be described as a separate generic entity of heterocytous cyanobacteria (although they have not been sequenced to date). The new genus Macrospermum is therefore defined in my article with 4 related, morphologically distinguishable species. The generic name is selected according to the unusually large akinetes.
MANN, D.G., THOMAS, S.J. & EVANS, K.M.: Revision of the diatom genus Sellaphora: a first account of the larger species in the British Isles.
As a step towards a global monograph of the freshwater diatom genus Sellaphora, we made detailed surveys of Sellaphora diversity in the epipelon of 38 lakes and ponds and three Holocene diatomites in the British Isles, restricting our analysis to those specimens that would be classified in S. americana, S. bacillum, S. pupula or S. laevissima according to the standard European diatom flora of KRAMMER & LANGE-BERTALOT (1986; Süsswasserflora von Mitteleuropa, vol. 2/1. – G. Fischer, Stuttgart & New York). From a total of c. 104 specimens observed, over 3200 were recorded as digital images and sorted into 54 mostly informally-named phenodemes that can act as operational taxonomic units during future revisions. Of the 54 phenodemes, c. 40 are well-differentiated, while the others seem to intergrade and are in particular need of further study using morphometric, molecular and mating approaches. The limitations of conventional diatom taxonomy by visual comparison are clearly demonstrated. To help standardize identifications, published DNA sequences are assigned to some of the demes as ‘molecular barcode’. The phenodemes of S. pupula sensu lato cannot be equated with the infraspecific taxa previously recorded for the British Isles and both these and most other pre-1990 records of species now assigned to Sellaphora must be regarded as having very little value for ecological and biogeographical purposes. Possible non-British records of the phenodemes are discussed but few are totally convincing; of those records most likely to be of the same phenodemes, the majority come from elsewhere in Europe.
KOMÁREK, J.: The cyanobacterial genus Macrospermum.
This small tropical cyanobacterial group, containing Anabaena volzii LEMMERMANN and a few related species (A. fuellebornii SCHMIDLE, A. unispora GARDNER, A. mysorensis GONZALVES & KAMAT), differs substantially phenotypically from all other planktic or benthic Anabaena types, mainly by the subsymmetric structure of the trichomes, type of akinete formation and restricted ecology. The taxonomic uniformity of all other Anabaenalike clusters (typical benthic Anabaena, planktic Anabaena subg. Dolichospermum, Trichormus, Aphanizomenon, Cuspidothrix) was already supported by molecular analyses. All of them also have their typical morphological markers, which are clearly different from the “Anabaena volzii – cluster”. Therefore, this group can not be classified in any of the mentioned revised genera and must be described as a separate generic entity of heterocytous cyanobacteria (although they have not been sequenced to date). The new genus Macrospermum is therefore defined in my article with 4 related, morphologically distinguishable species. The generic name is selected according to the unusually large akinetes.