Phayaothrix Tawong & T. Nishimura

Tawong, Wittaya, Nishimura, Tomohiro, Pongcharoen, Pongsanat, Saijuntha, Weerachai, Kucharoenphaibul, Siriwat, Sunpapao, Pathipat, Pongpadung, Piyawat & Ponza, Supat, 2024, Molecular characterization uncovering a novel genus of tapering-filamentous cyanobacteria from Thailand: Phayaothrix lacustris gen. & sp. nov. (Nostocales, Cyanophyta), Phytotaxa 647 (1), pp. 34-52 : 38

Phayaothrix Tawong & T. Nishimura gen. nov. ( Fig. 1 )

Description: —Filaments in groups not surrounded by abundant mucilage or gelatin, without radial disposition, entangled, long, branches rare, sheath present, usually thin and hyaline, opened at the apex, trichomes heteropolar or isopolar, usually constricted, cells of variable length, shorter or longer than wide, basal or intercalary heterocytes, single or in pairs, variable in shape, necridia present, akinetes absent, benthic inhabitant.

Type locality:— THAILAND. Phayao: Mueang Phayao , freshwater rock in Phayao Lake (Kwan Phayao), 21 June 2020 .

Type species: — Phayaothrix lacustris .

Etymology: —The name of the genus, Phayaothrix , refers to a cyanobacterial filament from Phayao Lake, Thailand, from which the type strain of this filamentous cyanobacterium was isolated.

Figures

FIGURE 1. Morphological variability of Phayaothrix lacustris strain NUACC09 using light microscopy. Scale bar 10 µm. (A–C) heteropolar filament without a hyaline hair at the terminal, (D) old filament showing a hyaline sheath and double intercalary heterocyte, (E–G) twist, coil or loop forming at the terminal and middle regions after cell division, (H–I) knotted growth form and undulating filament, (J–K) young growing filament with single branching (arrow), (L) filament with double branching (arrow), (M–N) heterocytes with senescing heterocytes, (O) second heterocyte forming next to an old terminal cell (arrow), (P–Q) various apical cells developing into heterocyte (arrow), (R) filament showing hormogonia (open square) and necridia (asterisk), (S–T) hormogonia forming heterocytes at one or both sides of terminal cells.