New taxa of Cosmarium and Euastrum (Zygnematophyceae) from the North Coast of Bahia, Brazil Author Costa, Fabiana De Matos 0000-0001-7892-5036 Programa de Pós-Graduação em Botânica, Laboratório de Ficologia, Universidade Estadual de Feira de Santana, Feira de Santana, BA, Brazil. famatoscosta@hotmail.com Author Ramos, Geraldo José Peixoto 0000-0003-2089-0461 Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus, BA, Brazil. gjpramos@uesc.br Author Moura, Carlos Wallace Do Nascimento 0000-0001-6904-6603 Programa de Pós-Graduação em Botânica, Laboratório de Ficologia, Universidade Estadual de Feira de Santana, Feira de Santana, BA, Brazil. wallace@uefs.br text Phytotaxa 2023 2023-12-28 632 2 193 200 https://phytotaxa.mapress.com/pt/article/download/phytotaxa.632.2.9/51403 journal article 283349 10.11646/phytotaxa.632.2.9 f9a10b12-c84f-4943-8789-7e8fc3d210e5 1179-3163 10438588 Cosmarium margigranulatum F.M. Costa & C.W.N.Moura sp. nov. ( Figs. 3 , 15–18 ) Diagnosis: —Cells as long as broad, median constriction deep, sinus closed, linear; semicells reniform, smooth median face, angles rounded covered by granules, apex slightly projected with three protrusions; cell oblong in apical view. Cell dimensions: length 36.8–41.3 μm, breadth 41.6–44.6 μm, breadth of isthmus 12.7–16.2 μm. Holotype :— Material numbered ( HUEFS 263036 !) [pro parte], deposited at the Herbarium of the State University of Feira de Santana , population partially illustrated here ( Figs. 3 , 15–18 ). Paratypes :— Material numbered ( HUEFS 263040) [pro parte], deposited at the Herbarium of State University of Feira de Santana. Type locality:— BRAZIL . Bahia : Camaçari, Camaçari-Mirim River, Lat. 12°42’23.1’’ S , Long. 38°15’27.2’’ W , 29 November 2019 , F . M . Costa & J . T .X. Neto s/n ( HUEFS 263036). Habitat:— Periphytic on Eleocharis acutangula ; water conductivity 0.04 mS. cm-1 (± 0.01); dissolved oxygen 7.6 mg .L- 1 (± 0.1); pH 7.3 (± 0.9); total dissolved solids 0.02 ppt (± 0.01); water temperature 28.3 ºC (± 1.3). Etymology:— The specific epithet refers to the ornamentation composed of various granules located at the margins of semicells. Differential diagnosis:— Cosmarium margigranulatum differs from the other species of Cosmarium by having a very distinct ornamentation: concentrated granules along the margins of the semicells, but lacking in the central region. Morphologically, the newly described species resembles Cosmarium ornatum var. pseudolagoense Förster (1964: 399) . However, this latter variety differs by having a concentric ring of granules on the face of the semicells and short spines at the angles of the semicells.