Timaviella dunensis Mikhailyuk & O.M. Vynogr., 2022

Mikhailyuk, Tatiana, Vinogradova, Oksana, Holzinger, Andreas, Glaser, Karin, Akimov, Yuri & Karsten, Ulf, 2022, Timaviella dunensis sp. nov. from sand dunes of the Baltic Sea, Germany, and emendation of Timaviella edaphica (Elenkin) O. M. Vynogr. & Mikhailyuk (Synechococcales, Cyanobacteria) based on an integrative approach, Phytotaxa 532 (3), pp. 192-208 : 198-205

Timaviella dunensis Mikhailyuk & O.M. Vynogr. sp. nov. ( Figs. 3 , 5 , 6 , H–M, Tab. 4 )

Diagnosis: Morphologically and ecologically similar to T. edaphica differing in the colorless sheath, wider filaments and trichomes, conical end cells, longer Box-B and D1-D1’ helices; structure of V3 helix in the position 9-50 and of basal stem and terminal loop in V2. Differs from T. circinata in Box-B and V3 helices length, the structure in the D1- D1’, Box-B and V3 helices, as well as the color of thallus, rare false branching, wider trichomes, parallel thylakoids and presence of necridia.

Description: Thallus radially spreading, expanded, leathery, brownish, dark olive, blue-green to light greenish. Filaments long, variously curved, (3.0) 3.8-4.9 (6.0) μm wide. False branching rare, mostly double. Sheath colourless, firm, thick. Trichomes slightly constricted at cross-walls, occasionally becoming almost biseriate due to oblique division and compression of cells, 2.2–3.3 μm wide. Cells cylindrical, isodiametric to longer than wide, with parietal thylakoids, 2.2–3.5 μm long. End cells rounded to conical. Necridia in both young and senescing trichomes, hormogonia rare. D1- D1’ helix 85 nucleotides long, with a 3’ unilateral bulge at position –/ 73-80, five internal loops at position 10/68, 14- 15/63-64, 20/58, 23/54-55 and 31/46. Terminal loop having sequence 5’-UCUC-3’. Box B helix 48 nucleotides long, with several assymetrical internal loops at position 6/41–42, 9–10/39 and –/30–32. Terminal loop 5 nucleotides long, 5’-AUAAU-3’. V2 helix 10 nucleotides long, terminal loop 4 nucleotides, 5’-AUUA-3’. V3 helix 60 nucleotides long, with several internal loops at positions 4/53–55, 9–10/47–50 and 23/34. Terminal loop having sequence 5’-GAAA-3’.

Etymology: Named for its occurrence in biocrusts on dunes; dunensis (L) = of dunes.

Holotype here designated: KW-A-32531, Algotheca, Herbarium of the M.G. Kholodny Institute of Botany of the National Academy of Sciences of Ukraine (KW), Kyiv, Ukraine.

Reference strain: Us-6-3 was deposited at the German Collection for Microorganisms and Cell Cultures ( DSM 112875), Braunschweig, Germany, as well as at culture collection of the M.G. Kholodny Institute of Botany of the National Academy of Sciences of Ukraine (IBASU-A-754).

Type locality: The coast of the Baltic Sea , Usedom Island, vicinity of Zempin, Germany, 54°04′17″ N 13°58′04″ E, collected on 8 October 2013 by Tatiana Mikhailyuk. Sand dunes, biocrusts with dominance of cyanobacteria and streptophyte algae .

Figures

FIGURE 3. Secondary structure of the main informative helices of region 16S-23S ITS of cultured strains of Timaviella. All differences between strains of T. edaphica (KZ-7-1) and T. dunensis (Us-6-3) are presented in comparison with the authentic strain of T. circinata (GR4). Variable bases are shown with arrows, places of insertions/deletions of base pairs are marked with arrowheads, homological base pairs among different strains are indicated with gray lines. Intraspecific variation inside T. edaphica are shown with the asterisk.

FIGURE 5. Timaviella dunensis (Us-6-3): A—overview of colony on the surface of agarized medium: thallus prostrate and in growing inside the medium; B, K—filaments in firm hyaline sheath; C—trichome without sheath; D—fragment of trichome with necridia; note elongated, discoid and obliquely dividing cells; E, G—loosely arranged filaments with geminate false branching; F—consecutive single and geminate false branching; H, I—fragments of filaments with trichomes twisted in the sheath; J—formation of hormogonia, cells with granulations. Scale bars: A—50 μm, B–K—10 μm.

FIGURE 6. Ultrastructure of original strains of Timaviella with characteristic position of thylakoids arranged more or less parallel in a parietal position. T. edaphica (KZ 7-1-2): fragments of trichomes without sheath (A), in multilayered sheath (B), constricted at cross walls, with cyanophycin granules; cells barrel-shaped, isodiametric (A) to elongated (G), end cells (D), trichomes in longitudinal section (E). T. edaphica (KZ 23-2): end cells (C), trichomes in longitudinal section (F). Timaviella dunensis (Us-6-3): fragments of trichomes in thick sheath (H, I), weakly constricted at cross walls; cells cylindrical, elongated, end cells (J–L); formation of necridia (M). S, sheath, Cy, cyanophycin granules, T, thylakoids. Scale bars = 1µm.