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 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