Anabaena wallumensis G. B. McGregor, 2018

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

Anabaena wallumensis G. B. McGregor sp. nov. Fig. 39 A–D.

Filaments entangled in loose mucilaginous clusters, dispersed among other cyanobacteria and microalgae in periphytic mats. Trichomes flexuous, ± irregularly coiled, deeply constricted at cross walls, not attenuated towards ends, 3.1– 5.0 μm wide, with a sub-symmetric structure, one heterocyte occurring every (10–) 24–40 (–52) vegetative cells. Vegetative cells barrel-shaped, isodiametric or up to 1.7 × longer than wide, (3.1–) 4.0–5.0 μm long × 5.6–7.5 (–8.5) μm wide, with granulated blue-green contents; apical cells rounded and undifferentiated. Heterocytes intercalary, sub-spherical to cylindrical, 1.5 × longer than wide, 4.5–7.0 μm long × 6.0–8.5 (–10) μm wide, occasionally in pairs. Akinetes rounded cylindrical, solitary and always adjacent to heterocytes, 2.2–2.7 × longer than wide, 7.5–11 μm long × 18–22 (–27) μm wide, endospore pale golden brown, exospore covered with flexuous hair-like processes, up to 6.3 μm in length.

Holotype:— Preserved specimen deposited in the Queensland Herbarium ( BRI), accession number AQ826841. Type locality: Moon Point Fens, Fraser Is. ( 25 o 12’48.84” S, 153 o 3’36.43” E). Etymology: the specific epithet refers to the indigenous Kabi word for the wallum banksia ( Banksia aemula R. Brown) which is used to describe coastal shrub and heathlands on deep, nutrient-poor, acidic sandy soils.

Specimens examined:—Boomerang Lakes, Lake Jennings, Moon Point Fens at Great Sandy Natl Park, Fraser Is. Section, Rainbow Beach Fens at Great Sandy Natl Park, Cooloola Section.

Observations:— A. wallumensis is morphological similar to a number of benthic species known from tropical and subtropical marshy habitats, which have large cylindrical akinetes adjacent to intercalary heterocytes ( A. fuscovaginata , A. iyengarii , A. oblonga , A. orientalis ). However, in A. wallumensis , the mature exospore is densely covered in distinctive, flexuous hair-like processes. The material was observed growing in the metaphyton of several shallow peaty wetlands amongst emergent sedges, and in the littoral areas of acidic perched lakes in SE Queensland.