Diatomella colonialis, a new diatom species (Bacillariophyta) from the sub-Antarctic Region

• Published in: Phytotaxa
• Main Authors: VAN DE VIJVER, BART, LE COHU, RENÉ
• Format: Article in Journal/Newspaper
• Language: English
• Published: Phytotaxa 2017
• Subjects: sub-Antarctica; Kerguelen; Diatomella; new species; colony formation; Algae; Antarctic; Indian; Antarc*; Antarctica
• Online Access: http://www.mapress.com/j/pt/article/view/phytotaxa.306.4.4; https://doi.org/10.11646/phytotaxa.306.4.4

During a survey of the freshwater diatom flora of the sub-Antarctic Kerguelen archipelago in the southern Indian Ocean, an unknown Diatomella taxon was observed forming long colonies using linking spines. Detailed morphological analysis based on light and scanning electron microscopical observations and comparison with all known Diatomella taxa worldwide justified the description of this unknown taxon as a new species: Diatomella colonialis sp. nov. The new taxon is characterized by the presence of marginal linking spines, the reduction of its raphe structure leaving only two short raphe slits near the apices, a very large axial area occupying almost the entire valve face and very short alveolate striae composed of paired areolae. The presence of these alveolate striae and the girdle structure with its typical scalariform valvocopula place this taxon in the genus Diatomella. The new species is described and compared with other Diatomella taxa. Notes on its distribution and ecology are added.