Phormidesmis arctica Raabová, Kovacik, Elster & Strunecký, 2019

Raabová, Lenka, Kovacik, Lubomir, Elster, Josef & Strunecký, Otakar, 2019, Review of the genus Phormidesmis (Cyanobacteria) based on environmental, morphological, and molecular data with description of a new genus Leptodesmis, Phytotaxa 395 (1), pp. 1-16 : 12

Phormidesmis arctica Raabová, Kovacik, Elster & Strunecký , sp. nov. ( Figs 1O–T , 2A , 6B )

Description: —Filaments straight or curved, solitary or irregularly arranged in clusters, or entangled, with one or more trichomes per sheath. Filaments pale blue-green, dark olive-green to yellow-brown. Filaments slightly constricted at the cross-walls. Sheaths are invisible in young cultures or thin, colorless, in old cultures getting thicker, colorless or brownish when exposed to strong light, sometimes lamellate. Filaments 1.5–3(4) μm wide. Cell length is 1–3(5) μm. Cells are barrel-shaped or shorter than wide, occasionally longer than wide. Central granules are characteristic. Specific nodi are present on filaments in old cultures, or scarcely falsely pseudobranched. Apical cells are rounded, without calyptra.

Habitat: —Known only from Arctic soils; Svalbard, Mummien peak near Petuniabukta.

Type: —Strain Mum 11-7 is held in the Culture Collection of Autotrophic Organisms at the Institute of Botany AS CR, Třeboň, Czech Republic as item no. 1101.

Figures

FIGURE 1. Microphotographs of different strains that illustrate the morphological variability of four species of the genus Phormidesmis: A–E P. nigrescens, F–I P. priestleyi, J–N P. communis, O–T P. arctica, and U–Z Leptodesmis paradoxa. Scale bar = 10μm.

FIGURE 2. Drawings of four species of the genus Phormidesmis: A—P. arctica, B—P. communis, C—P. priestleyi, D—P. nigrescens. Scale bar = 10μm.

FIGURE 6. Shape of colonies. A—Leptodesmis paradoxa (6 weeks old), B—Phormidesmis arctica (3 weeks old), C—Phormidesmis communis (6 weeks old), D—Phormidesmis nigrescens (3 week old), E—Phormidesmis nigrescens (9 weeks old), F—Phormidesmis priestleyi (6 weeks old).Arrow indicates the brownish color of colonies which can be commonly found in natural populations under high light.