Cyclotella deceusteriana, a new centric diatom species (Bacillariophyta) from the sub-Antarctic Region

Abstract

During a survey of the freshwater diatom flora of the sub-Antarctic region (Iles Kerguelen and Iles Crozet) in the southern Indian Ocean, an unknown Cyclotella taxon was observed that was formerly identified as the presumed cosmopolitan C. meneghinana. Detailed morphological analysis based on light and scanning electron microscopical observations and comparison with several similar Cyclotella taxa worldwide justified the description of this unknown taxon as a new species: Cyclotella deceusteriana sp. nov. The new taxon is characterized by the presence of marginal fultoportulae on every costa, hyaline furrows between the raised marginal parts on which the striae are located, 2, occasionally 1, 3 or 4 central fultoportulae and an entirely flat, smooth, relatively small central area. The new species is described and compared with other Cyclotella taxa. Notes on its distribution and ecology are added.