Review of the genus Phormidesmis (Cyanobacteria) based on environmental, morphological, and molecular data with description of a new genus Leptodesmis Author Raabová, Lenka Department of Biology, University of Ss. Cyril and Methodius, J. Herdu 2, 917 01 Trnava, Slovakia Author Kovacik, Lubomir Department of Botany, Comenius University in Bratislava, Révová 39, 811 02 Bratislava, Slovakia Author Elster, Josef Institute of Botany, Academy of Sciences of the Czech Republic, Dukelská 135, 379 82 Třeboň, Czech Republic & Faculty of Science, University of South Bohemia, Branišovská 135, 370 05 České Budějovice, Czech Republic Author Strunecký, Otakar Faculty of Science, University of South Bohemia, Branišovská 135, 370 05 České Budějovice, Czech Republic & Institute of Aquaculture, CENAKVA, Faculty of Fisheries and Protection of Waters, University of South Bohemia, Husova tř. 458, 370 05 České Budějovice, Czech Republic text Phytotaxa 2019 2019-03-06 395 1 1 16 http://dx.doi.org/10.11646/phytotaxa.395.1.1 journal article 302484 10.11646/phytotaxa.395.1.1 b074470c-7bbf-4be7-b081-1e7693c9f086 1179-3163 13718385 Leptodesmis paradoxa Raabová, Kovacik & Strunecký , sp. nov. ( Figs 1U–Z , 6A ) Description: —Filaments straight, curved, flexuose or wavy, solitary, one filament per sheath. Filaments pale blue-green to dark green, slightly constricted at cross-walls. Sheaths thick, colorless. Filaments 2.5–3.5(4) μm wide, occasionally with necridic cells. Cell length 1–2 μm. Cells barrel shaped or shorter than wide, occasionally longer than wide with central granules in cells. Apical cell is rounded without calyptra. Habitat: — Antarctica , South Shetlands, caldera Deception Island, mud of littoral pools. Etymology: — paradoxa means unexpected morphology, changing during the life cycle. Type : —Strain LK021 is held in the Culture Collection of Autotrophic Organisms at the Institute of Botany AS CR, Třeboň, Czech Republic as item no. 1104.