First detection of species of the potentially toxic genus Azadinium (Amphidomataceae, Dinophyceae) in tropical coastal waters of Brazil

In fall 1995, during a survey in Abrolhos coral reef system (southwestern Atlantic, Brazil), significant densities (143–6174 cells L-1) of small thecate dinoflagellates were detected. Analysis of this material in scanning and transmission electron microscopy confirmed the presence of four taxa assigned to the potentially toxic genus Azadinium: A. dexteroporum Percopo et Zingone, A. luciferelloides Tillmann et Akselman, A. cf. polongum Tillmann and Azadinium sp. The latter taxon showed external morphological features quite distinct from any Azadinium taxon yet described, but its formal description as a new species depends on more detailed analysis. Species of Azadinium have never been confirmed in Brazilian waters until now, although the toxins produced by these dinoflagellates, the azaspiracids, have been detected in Brazilian southern coast without recognition of their producing organisms. The highest densities of Azadinium spp. occurred at stations south of and over the Abrolhos Bank, which receive higher nutrient concentrations due to upwelling of deep and nutrient-rich water masses

Spirotaenia tetrahelica G. J. P. Ramos & C. W. N. Moura 2023, sp. nov.

<i>Spirotaenia tetrahelica</i> G.J.P.Ramos & C.W.N.Moura, <i>sp. nov</i>. (Figs. 1–4, 11) <p> <b>Diagnosis:</b> Cells 6–8 times longer than wide, broadly fusiform with rounded to slightly truncated poles. chloroplast ribbon-shaped, parietal, with four spiral ribbons that merge at the cell poles, sometimes with slightly reddish or brownish coloration at the ends. Cell dimensions: length 55–77.5 μm, width 9.5–10.5 μm.</p> <p> <b>Type</b>:— BRAZIL. Bahia: Lençóis, Lat. 12°29’04” S, Long. 41°28’23” W, 15 September 2022, <i>G. J. P</i> <i>.</i> <i>Ramos s/n</i> (Holotype HUESC 26222!).</p> <p> <b>Holotype</b>:—Material numbered (HUESC 26222!) [pro parte], deposited at Herbarium of State University of Santa Cruz, population partially illustrated here (Figs. 1–4, 11).</p> <p> <b>Ecology:—</b> puddle; metaphyton, pooled with various Cyperaceae and associated filamentous algae such as <i>Mougeotia</i> and <i>Spirogyra</i> spp.; abiotic water data: pH 4.3, temperature 25.4 ºC, conductivity 14 μS/cm, TDS 7 ppm, ORP 406 mV.</p> <p> <b>Etymology:—</b> The epithet is due to the four spiral ribbons of the chloroplast.</p> <p> <b> Distribution: <i>South America</i></b> : Brazil (present study).</p> <p> <b>Differential diagnosis:—</b> <i>Spirotaenia tetrahelica</i> differs from other species of the genus by having fusiform cells with rounded to slightly truncated poles and a chloroplast composed of four spiral ribbons that merge at the cell poles.</p> <p> At first glance, <i>Spirotaenia tetrahelica</i> could be confused with <i>S. diplohelica</i>, another notable <i>Spirotaenia</i> species with chloroplast having more than one parietal ribbon. However, the latter species is distinguished by the presence of only two loosely spiraled ribbons that merge into a reddish-colored cap at both cell poles, and by its smaller dimensions: length 25–40 μm, breadth 6–8 μm (Coesel & Meesters 2007). Although <i>S. tetrahelica</i> can also have a reddish/brownish-colored cap at the chloroplast ends, in our analyzed population, this pattern was less frequent and notable compared to other species such as <i>S. diplohelica</i> and <i>S. erythrocephala</i>. Furthermore, the chloroplast ribbons in <i>S. tetrahelica</i> are slightly thinner than those of <i>S. diplohelica</i>.</p> <p> In terms of morphology, <i>S. diplohelica</i> can still be mistaken for representatives of <i>Tortitaenia obscura</i> (Ralfs) Brook (1998: 146), primarily due to the presence of various helical ribbons in their chloroplasts. However, <i>Spirotaenia</i> species possess a parietal chloroplast forming one or more spiral ribbons, while <i>Tortitaenia</i> species have an axial chloroplast with multiple spiral ridges.</p>Published as part of <i>Ramos, Geraldo José Peixoto, Souza, Bruna Fadul De, Ribeiro, Sylvia Maria Moreira Susini & Moura, Carlos Wallace Do Nascimento, 2023, New insights into the diversity and distribution of the genus Spirotaenia (Mesotaeniaceae, Streptophyta) in the Neotropics, including the description of S. tetrahelica sp. nov., pp. 29-38 in Phytotaxa 613 (1)</i> on pages 30-31, DOI: 10.11646/phytotaxa.613.1.2, <a href="http://zenodo.org/record/8323664">http://zenodo.org/record/8323664</a&gt

Spirotaenia minuta Thuret 1856

Spirotaenia minuta Thuret (1856: 157) (Fig. 17) Cells 5 times longer than wide, fusiform with narrowly apices, chloroplast ribbon-shaped, parietal, constituted by a single loosely twisted helical ribbon. Cell length 32–33 μm, breadth 6 μm. Geographic distribution: Europe : Austria, France, Germany, Ireland, Latvia, Netherlands, Norway, Poland, Russian Federation, Spain, Ukraine, United Kingdom; North America: USA; Africa: South Africa (Cholnoky 1955), Asia: South Korea; Oceania: Australia and New Zealand (Guiry & Guiry 2023); South America: Argentina (Guarrera & Kuhnemann 1949, Tell 1985), Bolivia (Borge 1906). Ecology: Occurs in both hard- and soft-water situations (Prescott et al. 1972). Note: Spirotaenia minuta has been reported in Bolivia (Borge 1906), but the taxonomic information is limited to cell dimensions (32–33 µm in length, 6 µm in width, Borge 1906). Tell (1985) referenced Guarrera & Kuhnemann (1949) for Tierra del Fuego (Argentina), but did not provide detailed information. Therefore, further studies are recommended to confirm the occurrence of this species in the Neotropics.Published as part of Ramos, Geraldo José Peixoto, Souza, Bruna Fadul De, Ribeiro, Sylvia Maria Moreira Susini & Moura, Carlos Wallace Do Nascimento, 2023, New insights into the diversity and distribution of the genus Spirotaenia (Mesotaeniaceae, Streptophyta) in the Neotropics, including the description of S. tetrahelica sp. nov., pp. 29-38 in Phytotaxa 613 (1) on page 34, DOI: 10.11646/phytotaxa.613.1.2, http://zenodo.org/record/832366

Spirotaenia filiformis G. J. P. Ramos, C. E. M. Bicudo & C. W. N. Moura 2017

<i>Spirotaenia filiformis</i> G.J.P.Ramos, C.E.M.Bicudo & C.W.N.Moura (2017: 268) (Fig. 18) <p>Cells 17–31 times longer than broad, long-cylindrical, narrowed toward the poles, poles rounded. Cells straight or slightly curved. Chloroplast a parietal ribbon making 3.5–8.5 turns, pyrenoids in series, one per turn. Cell dimensions: length 26–94 μm, breadth 1.5–3 μm.</p> <p> <b> Geographic distribution: <i>South America</i>:</b> Brazil (Ramos <i>et al.</i> 2017).</p> <p> <b>Ecology:</b> plankton; bromeliad phytotelmata</p> <p> <b>Note:</b> This species was described a few years ago based on material collected in bromeliad tanks (phytotelm) in Bahia State, northeastern Brazil. To date, this remains the only known record, suggesting a possible endemic status within Brazil. Its thinnest and elongated cylindrical cells are remarkable, making this species easily to be identified within the genus.</p>Published as part of <i>Ramos, Geraldo José Peixoto, Souza, Bruna Fadul De, Ribeiro, Sylvia Maria Moreira Susini & Moura, Carlos Wallace Do Nascimento, 2023, New insights into the diversity and distribution of the genus Spirotaenia (Mesotaeniaceae, Streptophyta) in the Neotropics, including the description of S. tetrahelica sp. nov., pp. 29-38 in Phytotaxa 613 (1)</i> on page 34, DOI: 10.11646/phytotaxa.613.1.2, <a href="http://zenodo.org/record/8323664">http://zenodo.org/record/8323664</a&gt

Spirotaenia endospira W. Archer 1864

<i>Spirotaenia endospira</i> W.Archer (1864: 15) (Fig. 15) <p>Cells 2.3–4 times longer than broad, straight or very slightly curved, oblong-cylindrical with broadly rounded poles, chloroplast a parietal ribbon making 1–2.5 turns. Cell dimensions: length 7–18 μm, breadth 3–4.5 μm.</p> <p> <b>Geographic distribution:</b></p> <p> <i>Europe</i>: Austria, Britain, Czech Republic, France, Germany, Ireland, Latvia, Romania, Slovakia, Ukraine, United Kingdom (Guiry & Guiry 2023); <i>North America</i>: USA (Guiry & Guiry 2023); <i>Asia</i>: South Korea (Guiry & Guiry 2023); <i>South America</i>: Brazil (Ramos <i>et al.</i> 2017).</p> <p> <b>Ecology:</b> plankton, metaphyton; puddles, bromeliad phytotelmata</p>Published as part of <i>Ramos, Geraldo José Peixoto, Souza, Bruna Fadul De, Ribeiro, Sylvia Maria Moreira Susini & Moura, Carlos Wallace Do Nascimento, 2023, New insights into the diversity and distribution of the genus Spirotaenia (Mesotaeniaceae, Streptophyta) in the Neotropics, including the description of S. tetrahelica sp. nov., pp. 29-38 in Phytotaxa 613 (1)</i> on page 33, DOI: 10.11646/phytotaxa.613.1.2, <a href="http://zenodo.org/record/8323664">http://zenodo.org/record/8323664</a&gt

Spirotaenia beijerinckii Coesel 2002

<i>Spirotaenia beijerinckii</i> Coesel (2002: 72) (Figs. 5, 12) <p>Cells 5–8 times longer than wide, fusiform with narrowly apices, chloroplast ribbon-shaped, parietal, constituted by a single loosely twisted helical ribbon, with two tiny reddish dots at each end. Cell length 25–42 μm, breadth 4.5–5 μm.</p> <p> <b>Material examined:</b> Brazil, Bahia State, municipality of Uruçuca, Serra Grande, Parque Estadual Serra do Conduru, 20/IV/2023, 14°29’36” S 39°08’13” W, B. F. Souza (HUESC 26220).</p> <p> <b>Ecology:</b> pond; periphyton associated to aquatic macrophytes, including <i>Eleocharis</i> sp.; abiotic variables of water: pH 6.4, temperature 32.4 ºC, conductivity 24 μS/cm, TDS 12 ppm, ORP 177 mV.</p> <p> <b> Distribution: <i>Europe</i>:</b> Netherlands, Germany, United Kingdom (Brook & Williamson 2011, Guiry & Guiry 2023); <b> <i>South America</i>:</b> Brazil (present study).</p> <p> <b>Note:</b> <i>Spirotaenia beijerinckii</i> is a species that has only been documented in northern hemisphere countries so far. It typically inhabits oligotrophic and shallow environments characterized by acidic conditions (Coesel & Meesters 2007). Its prominent characteristic is the presence of two small red dots at each end of the chloroplast. This coloration may lead to confusion with <i>S. erythrocephala</i>, which can be distinguished by its more rounded cell poles and a continuously reddish chloroplast end, lacking the two small red dots found in <i>S. beijerinckii</i>.</p>Published as part of <i>Ramos, Geraldo José Peixoto, Souza, Bruna Fadul De, Ribeiro, Sylvia Maria Moreira Susini & Moura, Carlos Wallace Do Nascimento, 2023, New insights into the diversity and distribution of the genus Spirotaenia (Mesotaeniaceae, Streptophyta) in the Neotropics, including the description of S. tetrahelica sp. nov., pp. 29-38 in Phytotaxa 613 (1)</i> on page 31, DOI: 10.11646/phytotaxa.613.1.2, <a href="http://zenodo.org/record/8323664">http://zenodo.org/record/8323664</a&gt

Spirotaenia erythrocephala Itzigsohn

<i>Spirotaenia erythrocephala</i> Itzigsohn in Braun (1856: 46) (Figs. 6–10, 13) <p>Cells 6–8 times longer than wide, fusiform with rounded poles. Chloroplast broad, spiral, notably red at the ends. Cell dimensions: length 57–62 μm, width 6.5–7.5 μm.</p> <p> <b>Material examined:</b> Brazil, Bahia State, municipality of Lençóis, 15/IX/2022, 12°30’31” S 41°29’11” W, G. J. P. Ramos <i>et al.</i> (HUESC 26221).</p> <p> <b>Ecology:</b> metaphyton, puddle, backwater near Águas Claras waterfall; abiotic water data: pH 4.9, temperature 26.2 ºC, conductivity 10 μS/cm, TDS 0 ppm, ORP 431 mV.</p> <p> <b> Geographic distribution: <i>Europe</i></b> : Bulgaria, Czech Republic, Netherlands, Germany, Romania, Slovakia; United Kingdom (Guiry & Guiry 2023); <i>Africa</i>: Mozambique (Rino 1972); <i>Asia</i>: South Korea (Guiry & Guiry 2023); India (Animica & Palanisamy 2022), Turkey (Akar & Avci 2022); <i>North America</i>: USA (Matthews 2023); <i>South America</i>: Brazil (present study).</p> <p> <b>Note:</b> The primary characteristic of <i>S. erythrocephala</i> is the presence of chloroplast with a wide parietal ribbon that terminate in a reddish portion at the apices. In our analysis, a substantial population was observed, with numerous individuals reproducing through binary division. However, no zygospores of this species were found.</p> <p> In addition to the current record in Brazil, other reports of this species occurring outside of Europe are recent. Notably, Kim <i>et al.</i> (2020) documented its presence in South Korea, Animica & Palanisamy (2022) reported it in India, and Matthews (2023) observed representatives in northeast Washington (USA).</p>Published as part of <i>Ramos, Geraldo José Peixoto, Souza, Bruna Fadul De, Ribeiro, Sylvia Maria Moreira Susini & Moura, Carlos Wallace Do Nascimento, 2023, New insights into the diversity and distribution of the genus Spirotaenia (Mesotaeniaceae, Streptophyta) in the Neotropics, including the description of S. tetrahelica sp. nov., pp. 29-38 in Phytotaxa 613 (1)</i> on pages 31-33, DOI: 10.11646/phytotaxa.613.1.2, <a href="http://zenodo.org/record/8323664">http://zenodo.org/record/8323664</a&gt