Timaviella obliquedivisa Mai, Johansen et Bohunická, 2018

Mai, Truc, Johansen, Jeffrey R., Pietrasiak, Nicole, Bohunická, Markéta & Martin, Michael P., 2018, Revision of the Synechococcales (Cyanobacteria) through recognition of four families including Oculatellaceae fam. nov. and Trichocoleaceae fam. nov. and six new genera containing 14 species, Phytotaxa 365 (1), pp. 1-59 : 34-36

Timaviella obliquedivisa Mai, Johansen et Bohunická sp. nov.

Diagnosis: ―Similar to T. radians , but differing in the profuse single and double false-branching and the coloration of trichomes, as well as the shorter D1-D1’ helix. V3 helix almost identical in shape to V3 helix of Timaviella species WMT-WP7-NPA in shape and sequence ( Fig. 9j ). Box B helix also similar to both other species, but with notable differences in all conserved domains of the ITS region ( Figs. 6k , 7j , 8h , 9j ).

Description:— Colony radially spreading, compact, firm, leathery, sometimes mounded, dark green, with yellowed margins near senescence. Filaments, untapered to slightly tapered ( Figs. 17a–b ), with repeated single and double false branching ( Figs. 17c–e ), 2.0–3.2 (3.9) μm wide. Sheath usually thin, soft, colorless, rarely extended past trichome apex), up to 1.3 μm wide. Trichomes false branched, with some branches erect and almost perpendicular to the original axis of the trichome ( Fig. 17f–h ), not constricted at distinctly visible cross-walls, occasionally becoming almost biseriate due to oblique division and compression of cells ( Fig. 17f ), 2.0–2.9 μm wide. Necridia present, hormogonia rare. Cells cylindrical, shorter than wide to longer than wide, with parietal thylakoids, often with one large central granule, 1.8–2.7–(3.7) μm long.

D1-D1’ helix 63 nucleotides long, with a 3’ unilateral bulge of 8 nucleotides (5’-CAUCCCAA-3’). Mid-helix with a pair of nucleotide mismatch of U/U and two internal loops at position 14–15/41–42 and 20–23/32–36 which is separated from the terminal loop by a 5’-GC:GC-3’ clamp. Terminal loop having sequence 5’-GAAA-3’ ( Fig. 6k ). Box B helix 50 nucleotides long, with several internal loops at position 5/44–46, 8–9/41 and 25–25/31–35, an internal mismatch 5/44–46 probably due to an insertion of an adenine residue. Terminal loop 5 nucleotides long, 5’-UUAAU-3’ ( Fig. 7j ). V2 helix 29 nucleotides long, with one internal loop at position 5–6/23–25 ( Fig. 8h ). V3 helix 62 nucleotides long, with several internal loops at positions 4/55–57, 11–12/47–50 and 23/34–35, separated from the terminal loop by a 5’-GU:AG-3’ clamp ( Fig. 9j ).

Etymology:— obliquus (L.): oblique; divisus (L.) divided; referring to the obliquely dividing cells that give rise to biseriate trichomes.

Type locality: ―Big Horn Seep Wall, Grand Staircase-Escalante National Monument, 37°43.012’ N- 111°28.273’ W, collected on 15 August 2006 by Markéta Bohunická. Hanging garden (concave wet rock face in a grotto with vascular plants hanging from the rock) on a sandstone rock wall in the Carmel-Page formation, partly covered with organic debris, mosses and vascular plants, in the GSENM, Kane County, Utah, USA.

Holotype here designated:— BRY37787 !, Herbarium for Nonvascular Cryptogams, Monte L. Bean Museum, Provo, Utah.

Isotype here designated:— BRY 37788!, Herbarium for Nonvascular Cryptogams, Monte L. Bean Museum, Provo, Utah.

Reference strain:— GSE-PSE-MK28-08A, Algal Culture Collection at John Carroll University, Cleveland, USA. Additional reference strain: GSE-PSE-MK23-08B, Algal Culture Collection at John Carroll University, Cleveland, USA.

Taxonomic notes:— Attenuated trichomes, erect false branches, and oblique division leading to biseriate trichomes are the defining morphological characteristics of T. obliquedivisa . No previously described species is a match for these characteristics ( Sciuto et al. 2017). The secondary structures of the conserved ITS domains are unique in comparison with the same structures from other Oculatellaceae , but without exceptional features; they look similar to other Oculatellaceae in the basal clamps and absence of side branches. The conserved domains of the 16S–23S had secondary structures unique to this species (see Sciuto et al. 2017).

Figures

FIGURE 6. D1-D1’ stems of species described in Oculatellaceae.The stem structures of genera described previously in other publications (Oculatella, Thermoleptolyngbya, Timaviella) or in publications under provision (Trichotorquatus) are not shown here.

FIGURE 7. Box B helices of species described in Oculatellaceae. The structures of genera described previously in other publications (Oculatella, Thermoleptolyngbya, Timaviella) or in publications under provision (Trichotorquatus) are not shown here.

FIGURE 8. V2 helices of species described in Oculatellaceae. Several species do not have this structure, including Pegethrix convoluta, P. indistincta, Antartic Pegethrix species, Cartusia fontana¸ Kaiparowitsia implicata.

FIGURE 9. V3 helices of species described in Oculatellaceae. All species described have this structure. The V3 helix of Cartusia aeruginosa is missing because we do not have the full length of its ITS region.

FIGURE 17. Timaviella obliquedivisa. A–B. Slightly tapering filaments. C–E. Consecutive double and single false-branches in filaments resulting in branch-like structures. F–G. Cell division in oblique angles, causing geminate, knot-like branching or resembling to truebranching. H. Compact coiling of trichomes within sheath. Scale bar 10μm in 1000X magnification.