Anabaenopsis Miller (1923: 125)

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

Anabaenopsis Miller (1923: 125)

Type: A. elenkinii Miller (1923: 125)

Filamentous; trichomes solitary or sometimes arranged in tangled clusters; planktonic; circinate, sigmoidal or spirally coiled, seldom straight; without sheaths but producing diffluent, colourless, homogeneous mucilage; trichomes metameric with heterocytes developing intercalary in pairs at regular distances from one another. Trichomes often disintegrate soon after heterocyte formation at the position between heterocyte pairs. Vegetative cells short to long barrel-shaped or cylindrical, shorter up to several times longer than wide, pale blue-green, with aerotopes. Heterocytes terminal or intercalary, spherical or widely oval, rarely ovoid or elongated, rounded conical, usually slightly greater than vegetative cells. Akinetes spherical to broadly ovate, solitary or in series, intercalary, arising paraheterocytically, generally in the centre of trichomes.

A widely distributed genus of 32 species known from freshwater lakes and reservoirs, rivers and estuaries, more commonly throughout tropical and subtropical regons. Here four species are described from north-eastern Australia. Bibliography: Jeeji-Bai et al. (1977), Hindák (1988), Iteman et al. (2002), Komárek (2005), Rajaniemi et al. (2005), Santos et al. (2011), Aguilera et al. (2016).

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Filaments> 8 μm broad...................................................................................................................................................... A. arnoldii Filaments <8 μm broad......................................................................................................................................................................2 Filaments not or only slightly constricted at the cross walls........................................................................................ A. tanganyikae Filaments clearly constricted at the cross walls.................................................................................................................................3 Vegetative cells cylindrical, 4.5–10.5 μm long × (2.5–) 4–6 μm broad ........................................................................... A. circularis Vegetative cells barrel-shaped to long ellipsoid, 4.0–7.5 (–9) μm long × 4–6 (–8) μm broad.......................................... A. elenkinii