Sphaerospermopsis eucompacta (Li & Watanabe) Li & Li

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

Sphaerospermopsis eucompacta (Li & Watanabe) Li & Li in Li et al. (2015: 300) Fig. 23 A–G .

Basionym: Anabaena eucompacta Li & Watanabe (1999: 93)

Trichomes planktonic, solitary and regularly tightly coiled, without mucilaginous sheaths; coils (7.0–) 8.5–15.8 μm in diameter, distance between coils 4.2–8.7 μm. Vegetative cells spherical or slightly elongate, 2.4 –4.7 (–6.0) μm long × 2.8–4.2 μm broad, with aerotopes. Heterocytes spherical, 3.8–4.7 μm in diameter. Akinetes spherical to broadly ovoid, 6.3–8.8 μm long × 5.3–7.6 μm broad, adjacent to the heterocytes on one or both sides.

Specimens examined:—Moura offstream storage, Gattonvale offstream storage, Lake Clarendon, Bill Gunn Dam, Fitzroy R. at Moura Weir, Fitzroy R. at Neville Hewitt Weir, Fitzroy R. at Bedford Weir, Fitzroy R. at Theodore Weir, Fairbairn Dam, Wuruma Dam, Coolmunda Dam, Moogerah Dam, Burnett R. at Ben Anderson Barrage, Burnett R. at Ned Churchward Weir, Burnett R. at Claude Wharton Weir, Callide Dam, Kolan R. at Bucca Weir, Eungella Dam, Bjelke-Petersen Dam, Paradise Dam, Glenlyon Dam, Cania Dam, Teemburra Dam, Pioneer R. at Dumbleton Weir, Kinchant Dam.

Other records:— South Australia: River Murray , Swan Reach (as Anabaena spiroides f. spiroides ), Baker (1991) .

Observations:—This species is similar to Dolichospermum compactum (Nygaard) Wacklin, Hoffmann & Komárek (2009) with respect to the narrow, tightly coiled trichomes, however it differs by the position of the akinetes which are remote from the heterocytes (a feature often difficult to resolve with LM in such tightly compact coils). S. crassa X. Li & R. Li (2016) is distinguished from S. eucompacta by larger vegetative cells and heterocyte diameter. S. eucompacta was originally described from the plankton of L. Yatsuru, Japan.Australian populations are known from mesotrophic weir pools throughout north-eastern Australia and the lower River Murray, South Australia.

Sphaerospermopsis reniformis (Lemmermann) Zapomělová, Jezberová, Hrouzek, Hisem, Řeháková & Komárková (2010: 415) Fig. 24 A–C.

Basionym: Anabaena reniformis Lemmermann (1898: 155)

Filaments planktonic; trichomes irregularly spirally coiled, constricted at the cross walls. Vegetative cells barrel-shaped or sub-spherical, compressed at the poles, 4.0–6.0 (–8) μm long × 3.5–5.5 μm broad, with aerotopes; apical cells undifferentiated. Heterocytes spherical or ovate, intercalary, solitary, 4.0–7.0 μm in diameter. Akinetes spherical, 7.0– 10.5 (–12.5) μm in diameter, solitary or in pairs, adjacent either side of the heterocytes, epispore smooth, colourless.

Specimens examined:—Atkinson Dam, Beardmore Dam, Bill Gunn Dam, Bjelke-Petersen Dam, Boondooma Dam, Borumba Dam, Bowen R. at Bowen R. Weir, Burdekin Falls Dam, Burnett R. at Ben Anderson Barrage, Burnett R. at Claude Wharton Weir, Burnett R. at Jones Weir, Burnett R. at Kirar Weir, Burnett R. at Ned Churchward Weir, Callide Dam, Cania Dam, Condamine R. at Chinchilla Weir, Coolmunda Dam, Corella Dam, Crookes Dam, Eungella Dam, Fairbairn Dam, Fitzroy R. at Bedford Weir, Fitzroy R. at Bingegang Weir, Fitzroy R. at Eden Bann Weir, Fitzroy R. at Glebe Weir, Fitzroy R. at Moura Weir, Fitzroy R. at Neville Hewitt Weir, Fitzroy R. at Tartrus Weir, Fitzroy R. at Theodore Weir, Fred Haigh Dam, Gattonvale offstream storage, Glen Niven Dam, Glenlyon Dam, Haughton R. at Giru Weir, Hinze Dam, Horn Is. Dam, Ibis Dam, Julius Dam, Jumna Dam, Kinchant Dam, Kolan R. at Bucca Weir, Lake Clarendon, Leslie Dam, Loudon Dam, Maroon Dam, Mary R. at Mary R. Barrage, Moogerah Dam, Moura offstream storage, Paradise Dam, Peter Faust Dam, Pioneer R. at Dumbleton Weir, Pioneer R. at Marian Weir, Pioneer R. at Mirani Weir, Six Mile Ck at Bajool Weir, Teemburra Dam, Tinaroo Falls Dam, Warrego R. at Allan Tannock Weir, Wuruma Dam, Wivenhoe Dam, Wyndham Dam.

Other records:— South Australia: River Murray at Swan Reach, Farm dam, Mount Barker , Baker (1991) (as Anabaena spiroides morphotype 2) ; Victoria: Iraak Ck downstream of Nangiloc, Humpage et al. (2013).

Observations:—Common and widespread species known from the plankton of reservoirs and weir pools throughout Australia. Shape and position of the akinete adjacent either side of the heterocyte is a distinctive morphological feature.

2. GLOEOTRICHACEAE

Gloeotrichiaceae Komárek, Kaštovský, Mareš & Johansen (2014: 315)

Type: Gloeotrichia Agardh ex Bornet & Flahault (1886: 365)

Thallus spherical, hemispherical, or irregularly shaped, mucilaginous, sometimes hollow, often macroscopic.Trichomes heteropolar with basal heterocytes and sub-terminal akinetes.

GLOEOTRICHIA

Figures

FIGURE 23. A–G Sphaerospermopsis eucompacta (arrows indicate position of akinetes). Scale bars = 20 μm