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 Author Mai, Truc Department of Biology, John Carroll University, 1 John Carroll Blvd., University Heights, Ohio 44118, USA & Department of Plant and Environmental Sciences, New Mexico State University, Skeen Hall Room N 127, P. O Box 30003 MSC 3 Q, Las Cruces, New Mexico 88003, USA. Author Johansen, Jeffrey R. Department of Biology, John Carroll University, 1 John Carroll Blvd., University Heights, Ohio 44118, USA & Department of Botany, Faculty of Science, University of South Bohemia, 31 Branišovská, 37005 České Budějovice, Czech Republic Author Pietrasiak, Nicole Department of Plant and Environmental Sciences, New Mexico State University, Skeen Hall Room N 127, P. O Box 30003 MSC 3 Q, Las Cruces, New Mexico 88003, USA. Author Bohunická, Markéta Author Martin, Michael P. Department of Biology, John Carroll University, 1 John Carroll Blvd., University Heights, Ohio 44118, USA text Phytotaxa 2018 2018-08-16 365 1 1 59 http://dx.doi.org/10.11646/phytotaxa.365.1.1 journal article 10.11646/phytotaxa.365.1.1 1179-3163 13704923 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. 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. 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 ).