Phormidesmis nigrescens (Komárek) 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 : 12-13

Phormidesmis nigrescens (Komárek) Raabová, Kovacik, Elster & Strunecký , comb. nov. ( Figs 1A–E , 2D , 6D– E )

Basionym: — Leptolyngbya nigrescens Komárek, Polish Polar Research 28(3): 221, 2007.

Synonym: — Leptolyngbya sieminskae ( Richter & Matuła 2013) , Phormidium melanochroun ( Lamprinou et al. 2013) .

Description: —Filaments long, straight or curved, solitary or sometimes in ± irregular clusters with more filaments per sheaths. Filaments sometimes entangled. Sheaths thick in young cultures, colorless or grey. In old cultures sheaths firm, lamellate, violet or blackish, sometimes open at the end. Filaments slightly constricted at the end, occasionally with necridic cells. Distinct nodi sometimes occur on filaments in old cultures. Cells are barrel-shaped. Central granules are present in center of cells. Filaments are 1.5–2.5(4) μm wide and 1–2(3.8) μm long. Apical cells are rounded, without calyptra.

Habitat: —Wet rocks, surface of bones, cave walls; very similar strains are known from the littoral of lakes and from thermal springs; deglaciated areas in the Arctic, Antarctica, in Greece (caves), probably distributed worldwide.

Type: —Strain RL 08-6 is held in the Culture Collection of Autotrophic Organisms at the Institute of Botany AS CR, Třeboň, Czech Republic as item no1102.

Note: —The whole genome shotgun sequence of this species is available at DDBJ /ENA/GenBank under the accession MPPI 00000000 ( Lara et al. 2017).

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.