Sirenicapillaria rigida D.E. Berthold, Lefler & Laughinghouse, 2022

Berthold, David E., Lefler, Forrest W. & Laughinghouse, H. Dail, 2022, Recognizing novel cyanobacterial diversity in marine benthic mats, with the description of Sirenicapillariaceae fam. nov., two new genera, Sirenicapillaria gen. nov. and Tigrinifilum gen. nov., and seven new species, Phycologia 61 (2), pp. 146-165 : 148

Sirenicapillaria rigida D.E. Berthold, Lefler & Laughinghouse sp. nov.

Figs 7–15

DESCRIPTION: Thallus dark brown, tangled, web-like. Filaments straight and rigid, 5 cm long, 28–83(–94) µm wide with thick, lamellate hyaline sheath. Trichomes cylindrical, 22.8–63.3 µm wide, thicker in the middle and gradually attenuated towards apices. Cells slightly constricted at cross walls. Cells discoid, wider than long, 1.8–3.9 µm long. Cell content light to dark brown, with pigmentless cells towards apices. Apical cell rounded, at times conical, with occasional calyptra. Reproduction by release of individual cells, straight or diagonal trichome fragmentation, necridia, hormogonia.

COMMENT: Individual filaments observed with naked eye and reminiscent of the freshwater Microseira wollei . Hormogonia form attached clumps on individual filaments.

TYPE LOCALITY: USA. Florida: Duck Key (24°46.635 ʹ N, 80°54.527 ʹ W) .

HABITAT: Benthic, wrapped around seagrasses in marine coasts.

ETYMOLOGY: Latin adjective rigidus, -a, -um, in reference to the physical rigidity of the filaments.

HOLOTYPE: US 227691 (dried material in a metabolically inactive state of reference strain BLCC-M116 ), deposited in US National Herbarium, National Museum of Natural History, Smithsonian Institution , Washington, DC, USA.

REFERENCE STRAIN: BLCC-M 116.

MATERIALS ANALYSED: BLCC-M 116 ( US 227691), BLCC-M 134 ( US 227777).

Figures

Figs 7–15. Microscope images of Sirenicapillaria rigida (reference strain BLCC-M116). Fig. 7. Rigid filament sheath and bending. Scale bar = 100 µm. Fig. 8. Clump of hormogonia usually attached to filaments. Scale bar = 100 µm. Fig. 9. Reduced pigmentation towards the apices. Scale bar = 100 µm. Fig. 10. Difference between a long filament centre with a sheath and apices without. Scale bar = 50 µm. Fig. 11. Necridia. Scale bar = 50 µm. Fig. 12. Filament slight diagonal fragmentation. Scale bar = 50 µm. Fig. 13. Extensive mucilaginous sheath. Scale bar = 50 µm. Fig. 14. Coarse and lamellate sheath. Scale bar = 50 µm. Fig. 15. Hormogonium with calyptra. Scale bar = 50 µm.