Symphyonema kaboorum G. B. McGregor, 2018

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

Symphyonema kaboorum G. B. McGregor sp. nov. Figs. 86 A–F, 87 A–D, 88 A–D, 89 A–F .

Thallus pulvinate, formed by more or less parallel arranged filaments. Filaments 11–17 μm wide, erect, straight to irregularly flexuous, not tapered towards the ends, not constricted at the cross walls, surrounded by a firm, hyaline mucilage, up to 25 μm wide, lamellated closer to the trichome; with false-branching, and T- and Y-type true branching, lateral branches often slightly narrower than main filament. Vegetative cells isodiametric, or up to 4 × longer than broad, shorter than broad towards the apices, (8.5–) 12.5–18.5 (–26) μm long × 4.8–10.5 μm wide, with fine granular contents, often vacuolate; apical cells rounded. Heterocytes solitary, intercalary, rarely located at the point of branching, spherical to elongated cylindrical, up to 3.5 × longer than broad, 9.0–18.5 (–26) μm long × 5.5–13.8 μm wide.

Holotype:— Preserved specimen deposited in the Queensland Herbarium ( BRI), accession number AQ826843. Type locality: Blue L., Naree Budjong Djara Natl Park, North Stradbroke Is. (27 o 32’01” S, 153 o 29’05” E). Etymology: the specific epithet refers to the indigenous Quandamooka word for Blue L. – Karboora.

Specimens examined:—Blue L., Naree Budjong Djara Natl Park, North Stradbroke Is.

Observations:—Aquatic; colonies forming expanded pulvinate growths on the upper surface of large, submerged logs and woody debris in the littoral zone of an acidic, coastal oligotrophic lake. There are no other aquatic species known from this genus; one epilithic species is known from limestone caves in Spain, and one aerophytic species known from French Guiana. The Y-type branching of this species is distinctive, often occurring in short succession, forming compound, M-type arrangements. Repeated efforts to isolate and sequence this species has not yet been successful. Here it is designated as a new species based on morphological and ecological criteria, which clearly separate it from existing Symphyonema species.

9. TOLYPOTHRICHACEAE

Tolypothrichaceae Hauer et al. (2014: 1093)

Type: Tolypothrix Kützing ex Bornet & Flahault (1886: 118)

Filaments polarized with mainly basal, uniporous heterocytes. Single false branching common, double branching occurring sporadically. Sheath thick or thin, but always present, sometimes yellow to yellow brown in colour. Vegetative cells isodiametric or shorter or longer than wide. Trichomes not or very slightly attenuated toward the ends. Reproduction by hormogonia with heteropolar germination, hormocytes, or trichome disintegration. Known from terrestrial, freshwater and marine habitats.

Figures

FIGURE 89. A–F Illustrations of true-branching types in Symphyonema kaboorum. Scale bars = 20 μm