Anabaenopsis arnoldii Aptekar (1926: 54)

Mcgregor, Glenn B., 2018, Freshwater Cyanobacteria of North-Eastern Australia: 3. Nostocales, Phytotaxa 359 (1), pp. 448-450 : 448-450

Anabaenopsis arnoldii Aptekar (1926: 54) Fig. 2 A–D.

Filaments planktonic; trichomes solitary or clustered in small colonies, ± irregularly screw-like coiled, coils 25–60 μm in diameter, constricted at the cross walls, with wide, colourless, diffluent mucilage. Vegetative cells spherical or widely barrel-shaped, distinctly compressed at the poles, grey-blue to yellow-green in colour, with aerotopes, (4–) 8–10 μm broad. Heterocytes spherical to widely oval, 5–11 μm long × 5.0–10.5 μm broad. Akinetes solitary or in pairs, widely elliptical, with colourless epispore, 10–19 (–22) long × 8–14 (–19) μm.

Specimens examined:—Carbrook Lakes.

Other records:— South Australia: Pelican Point at Lake Alexandrina, Campbell Park at Lake Albert, Gumeracha Weir, River Torrens , Baker (1991) ; Victoria: Ling & Tyler (2000); Northern Territory: Magela Ck, Thomasson (1986).

Observations:—Known from brackish coastal lagoons and occasionally estuaries. Associated with blooms of N. spumigena in Carbrook Lakes, south-east Queensland ( McGregor et al. 2012).