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Amphidinium operculatum, LM and SEM. (A) Cell from natural sample from western Australia, thick arrow points to pusule and sulcal origin, thin arrow points to cingular shape. (B) Dorsal view of cell from culture CAWD42, thin arrow points to posterior nucleus. (C) Cell from K-0663 showing posterior flagellar insertion. (D) Cell from natural sample from Sydney showing elongated plastids. (E) Cells from culture K-0663 showing cell division by binary fission. (F) Cell from natural sample from Sydney showing round inclusion (''stigma''). Scale bar, 10 mm. 

Amphidinium operculatum, LM and SEM. (A) Cell from natural sample from western Australia, thick arrow points to pusule and sulcal origin, thin arrow points to cingular shape. (B) Dorsal view of cell from culture CAWD42, thin arrow points to posterior nucleus. (C) Cell from K-0663 showing posterior flagellar insertion. (D) Cell from natural sample from Sydney showing elongated plastids. (E) Cells from culture K-0663 showing cell division by binary fission. (F) Cell from natural sample from Sydney showing round inclusion (''stigma''). Scale bar, 10 mm. 

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... Cells are ovoid to ellipsoidal in shape, with the greatest width between the cell center and the posterior end and dorsoventrally flattened. Cells are 29-50 mm long and 21-28 mm wide (for individual strains see Table 2). The right side of the hypocone is convex, whereas the left is almost straight (Fig. 1A). A small epicone overlays the anterior central part of the hypocone. In ventral view, the epicone is irregular triangular with the anterior left tip clearly deflected to the left. The epicone is 7-10 mm wide and anteriorly fairly flat (Fig. 1A). The angle of the anterior right tip is almost 90 degrees, with the anterior left tip forming an angle of approximately 30 degrees. The deeply incised cingulum originates 0.3 cell lengths from the anterior of the cell. The cingulum is displaced and slightly descending, with an angle of approximately 45 degrees between the proximal and distal ends. The sulcus originates in the lower one third of the cell and just to the right of the central axis ( Fig. 1, A and C). It is initially narrow but widens as it approaches the antapex. A narrow ventral ridge runs between the two points of flagellar insertion. The multiple plastids are yellow-brown and elongated, appearing to radiate to the cell periphery, but scattered near the center (Figs. 1D and 3A). No pyrenoid is visible. The nucleus is crescent shaped or oval, in the posterior of the cell, and with delicate thread-like chromosomes (Fig. 1B). Just above the nucleus, one orange-yellow, round, globular inclusions is often visible (Fig. 1F), with a diameter of 6-8 mm. Rarely, several inclusions were observed. Two pusules are present, lying in close proximity to the origin of the transverse and long- itudinal flagella, with a diameter of approximately 2 mm (Fig. 1A). Colorless globules ;are sometimes present, as are assimilation granules. Asexual division is by binary fission in the motile cell (Fig. ...
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... Cells are ovoid to ellipsoidal in shape, with the greatest width between the cell center and the posterior end and dorsoventrally flattened. Cells are 29-50 mm long and 21-28 mm wide (for individual strains see Table 2). The right side of the hypocone is convex, whereas the left is almost straight (Fig. 1A). A small epicone overlays the anterior central part of the hypocone. In ventral view, the epicone is irregular triangular with the anterior left tip clearly deflected to the left. The epicone is 7-10 mm wide and anteriorly fairly flat (Fig. 1A). The angle of the anterior right tip is almost 90 degrees, with the anterior left tip forming an angle of approximately 30 degrees. The deeply incised cingulum originates 0.3 cell lengths from the anterior of the cell. The cingulum is displaced and slightly descending, with an angle of approximately 45 degrees between the proximal and distal ends. The sulcus originates in the lower one third of the cell and just to the right of the central axis ( Fig. 1, A and C). It is initially narrow but widens as it approaches the antapex. A narrow ventral ridge runs between the two points of flagellar insertion. The multiple plastids are yellow-brown and elongated, appearing to radiate to the cell periphery, but scattered near the center (Figs. 1D and 3A). No pyrenoid is visible. The nucleus is crescent shaped or oval, in the posterior of the cell, and with delicate thread-like chromosomes (Fig. 1B). Just above the nucleus, one orange-yellow, round, globular inclusions is often visible (Fig. 1F), with a diameter of 6-8 mm. Rarely, several inclusions were observed. Two pusules are present, lying in close proximity to the origin of the transverse and long- itudinal flagella, with a diameter of approximately 2 mm (Fig. 1A). Colorless globules ;are sometimes present, as are assimilation granules. Asexual division is by binary fission in the motile cell (Fig. ...
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... Cells are ovoid to ellipsoidal in shape, with the greatest width between the cell center and the posterior end and dorsoventrally flattened. Cells are 29-50 mm long and 21-28 mm wide (for individual strains see Table 2). The right side of the hypocone is convex, whereas the left is almost straight (Fig. 1A). A small epicone overlays the anterior central part of the hypocone. In ventral view, the epicone is irregular triangular with the anterior left tip clearly deflected to the left. The epicone is 7-10 mm wide and anteriorly fairly flat (Fig. 1A). The angle of the anterior right tip is almost 90 degrees, with the anterior left tip forming an angle of approximately 30 degrees. The deeply incised cingulum originates 0.3 cell lengths from the anterior of the cell. The cingulum is displaced and slightly descending, with an angle of approximately 45 degrees between the proximal and distal ends. The sulcus originates in the lower one third of the cell and just to the right of the central axis ( Fig. 1, A and C). It is initially narrow but widens as it approaches the antapex. A narrow ventral ridge runs between the two points of flagellar insertion. The multiple plastids are yellow-brown and elongated, appearing to radiate to the cell periphery, but scattered near the center (Figs. 1D and 3A). No pyrenoid is visible. The nucleus is crescent shaped or oval, in the posterior of the cell, and with delicate thread-like chromosomes (Fig. 1B). Just above the nucleus, one orange-yellow, round, globular inclusions is often visible (Fig. 1F), with a diameter of 6-8 mm. Rarely, several inclusions were observed. Two pusules are present, lying in close proximity to the origin of the transverse and long- itudinal flagella, with a diameter of approximately 2 mm (Fig. 1A). Colorless globules ;are sometimes present, as are assimilation granules. Asexual division is by binary fission in the motile cell (Fig. ...
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... Cells are ovoid to ellipsoidal in shape, with the greatest width between the cell center and the posterior end and dorsoventrally flattened. Cells are 29-50 mm long and 21-28 mm wide (for individual strains see Table 2). The right side of the hypocone is convex, whereas the left is almost straight (Fig. 1A). A small epicone overlays the anterior central part of the hypocone. In ventral view, the epicone is irregular triangular with the anterior left tip clearly deflected to the left. The epicone is 7-10 mm wide and anteriorly fairly flat (Fig. 1A). The angle of the anterior right tip is almost 90 degrees, with the anterior left tip forming an angle of approximately 30 degrees. The deeply incised cingulum originates 0.3 cell lengths from the anterior of the cell. The cingulum is displaced and slightly descending, with an angle of approximately 45 degrees between the proximal and distal ends. The sulcus originates in the lower one third of the cell and just to the right of the central axis ( Fig. 1, A and C). It is initially narrow but widens as it approaches the antapex. A narrow ventral ridge runs between the two points of flagellar insertion. The multiple plastids are yellow-brown and elongated, appearing to radiate to the cell periphery, but scattered near the center (Figs. 1D and 3A). No pyrenoid is visible. The nucleus is crescent shaped or oval, in the posterior of the cell, and with delicate thread-like chromosomes (Fig. 1B). Just above the nucleus, one orange-yellow, round, globular inclusions is often visible (Fig. 1F), with a diameter of 6-8 mm. Rarely, several inclusions were observed. Two pusules are present, lying in close proximity to the origin of the transverse and long- itudinal flagella, with a diameter of approximately 2 mm (Fig. 1A). Colorless globules ;are sometimes present, as are assimilation granules. Asexual division is by binary fission in the motile cell (Fig. ...
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... Cells are ovoid to ellipsoidal in shape, with the greatest width between the cell center and the posterior end and dorsoventrally flattened. Cells are 29-50 mm long and 21-28 mm wide (for individual strains see Table 2). The right side of the hypocone is convex, whereas the left is almost straight (Fig. 1A). A small epicone overlays the anterior central part of the hypocone. In ventral view, the epicone is irregular triangular with the anterior left tip clearly deflected to the left. The epicone is 7-10 mm wide and anteriorly fairly flat (Fig. 1A). The angle of the anterior right tip is almost 90 degrees, with the anterior left tip forming an angle of approximately 30 degrees. The deeply incised cingulum originates 0.3 cell lengths from the anterior of the cell. The cingulum is displaced and slightly descending, with an angle of approximately 45 degrees between the proximal and distal ends. The sulcus originates in the lower one third of the cell and just to the right of the central axis ( Fig. 1, A and C). It is initially narrow but widens as it approaches the antapex. A narrow ventral ridge runs between the two points of flagellar insertion. The multiple plastids are yellow-brown and elongated, appearing to radiate to the cell periphery, but scattered near the center (Figs. 1D and 3A). No pyrenoid is visible. The nucleus is crescent shaped or oval, in the posterior of the cell, and with delicate thread-like chromosomes (Fig. 1B). Just above the nucleus, one orange-yellow, round, globular inclusions is often visible (Fig. 1F), with a diameter of 6-8 mm. Rarely, several inclusions were observed. Two pusules are present, lying in close proximity to the origin of the transverse and long- itudinal flagella, with a diameter of approximately 2 mm (Fig. 1A). Colorless globules ;are sometimes present, as are assimilation granules. Asexual division is by binary fission in the motile cell (Fig. ...
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... Cells are ovoid to ellipsoidal in shape, with the greatest width between the cell center and the posterior end and dorsoventrally flattened. Cells are 29-50 mm long and 21-28 mm wide (for individual strains see Table 2). The right side of the hypocone is convex, whereas the left is almost straight (Fig. 1A). A small epicone overlays the anterior central part of the hypocone. In ventral view, the epicone is irregular triangular with the anterior left tip clearly deflected to the left. The epicone is 7-10 mm wide and anteriorly fairly flat (Fig. 1A). The angle of the anterior right tip is almost 90 degrees, with the anterior left tip forming an angle of approximately 30 degrees. The deeply incised cingulum originates 0.3 cell lengths from the anterior of the cell. The cingulum is displaced and slightly descending, with an angle of approximately 45 degrees between the proximal and distal ends. The sulcus originates in the lower one third of the cell and just to the right of the central axis ( Fig. 1, A and C). It is initially narrow but widens as it approaches the antapex. A narrow ventral ridge runs between the two points of flagellar insertion. The multiple plastids are yellow-brown and elongated, appearing to radiate to the cell periphery, but scattered near the center (Figs. 1D and 3A). No pyrenoid is visible. The nucleus is crescent shaped or oval, in the posterior of the cell, and with delicate thread-like chromosomes (Fig. 1B). Just above the nucleus, one orange-yellow, round, globular inclusions is often visible (Fig. 1F), with a diameter of 6-8 mm. Rarely, several inclusions were observed. Two pusules are present, lying in close proximity to the origin of the transverse and long- itudinal flagella, with a diameter of approximately 2 mm (Fig. 1A). Colorless globules ;are sometimes present, as are assimilation granules. Asexual division is by binary fission in the motile cell (Fig. ...
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... Cells are ovoid to ellipsoidal in shape, with the greatest width between the cell center and the posterior end and dorsoventrally flattened. Cells are 29-50 mm long and 21-28 mm wide (for individual strains see Table 2). The right side of the hypocone is convex, whereas the left is almost straight (Fig. 1A). A small epicone overlays the anterior central part of the hypocone. In ventral view, the epicone is irregular triangular with the anterior left tip clearly deflected to the left. The epicone is 7-10 mm wide and anteriorly fairly flat (Fig. 1A). The angle of the anterior right tip is almost 90 degrees, with the anterior left tip forming an angle of approximately 30 degrees. The deeply incised cingulum originates 0.3 cell lengths from the anterior of the cell. The cingulum is displaced and slightly descending, with an angle of approximately 45 degrees between the proximal and distal ends. The sulcus originates in the lower one third of the cell and just to the right of the central axis ( Fig. 1, A and C). It is initially narrow but widens as it approaches the antapex. A narrow ventral ridge runs between the two points of flagellar insertion. The multiple plastids are yellow-brown and elongated, appearing to radiate to the cell periphery, but scattered near the center (Figs. 1D and 3A). No pyrenoid is visible. The nucleus is crescent shaped or oval, in the posterior of the cell, and with delicate thread-like chromosomes (Fig. 1B). Just above the nucleus, one orange-yellow, round, globular inclusions is often visible (Fig. 1F), with a diameter of 6-8 mm. Rarely, several inclusions were observed. Two pusules are present, lying in close proximity to the origin of the transverse and long- itudinal flagella, with a diameter of approximately 2 mm (Fig. 1A). Colorless globules ;are sometimes present, as are assimilation granules. Asexual division is by binary fission in the motile cell (Fig. ...
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... Cells are ovoid to ellipsoidal in shape, with the greatest width between the cell center and the posterior end and dorsoventrally flattened. Cells are 29-50 mm long and 21-28 mm wide (for individual strains see Table 2). The right side of the hypocone is convex, whereas the left is almost straight (Fig. 1A). A small epicone overlays the anterior central part of the hypocone. In ventral view, the epicone is irregular triangular with the anterior left tip clearly deflected to the left. The epicone is 7-10 mm wide and anteriorly fairly flat (Fig. 1A). The angle of the anterior right tip is almost 90 degrees, with the anterior left tip forming an angle of approximately 30 degrees. The deeply incised cingulum originates 0.3 cell lengths from the anterior of the cell. The cingulum is displaced and slightly descending, with an angle of approximately 45 degrees between the proximal and distal ends. The sulcus originates in the lower one third of the cell and just to the right of the central axis ( Fig. 1, A and C). It is initially narrow but widens as it approaches the antapex. A narrow ventral ridge runs between the two points of flagellar insertion. The multiple plastids are yellow-brown and elongated, appearing to radiate to the cell periphery, but scattered near the center (Figs. 1D and 3A). No pyrenoid is visible. The nucleus is crescent shaped or oval, in the posterior of the cell, and with delicate thread-like chromosomes (Fig. 1B). Just above the nucleus, one orange-yellow, round, globular inclusions is often visible (Fig. 1F), with a diameter of 6-8 mm. Rarely, several inclusions were observed. Two pusules are present, lying in close proximity to the origin of the transverse and long- itudinal flagella, with a diameter of approximately 2 mm (Fig. 1A). Colorless globules ;are sometimes present, as are assimilation granules. Asexual division is by binary fission in the motile cell (Fig. ...
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... analysis based on partial LSU rDNA. The phylogenetic analyses based on partial LSU rDNA using BA (Fig. 9) and ML (Fig. 10) resulted in trees with similar topologies. In both analyses, most branches were very well supported by either boot- strap analysis (Fig. 10) or high posterior probability (PP) values (Fig. 9). The main difference between the two analyses was in the sister-group relation- ship of the clade containing A. carterae, A. massartii, A. gibbosum, and A. trulla. In the BA analysis, this clade was found to be the sister group to the clade containing A. steinii, A. mootonorum, and A. herdmanii ( Fig. 9), whereas in the analysis using ML, this clade was found to be the sister group to A. operculatum (Fig. 10). In both phylogenetic analyses, the species A. steinii, A. operculatum, A. gibbosum, A. carterae, and A. trulla formed clades that were clearly separated from one another ( Figs. 9 and 10). Within these clades, some variation was found, with A. steinii strains differing from each other by 0.5%, excluding the hypervariable D2 region, and A. operculatum strains differing by 0- 1.0% (Table 3). The species A. carterae formed a clade, but within that three distinct clades were found that differed from each other by about 40 fixed base differences (up to 1.7% excluding the D2 region) (Figs. 9 and 10, Table 3). The strains of A. massartii did not form a single clade. In both analyses, two lineages of A. massartii were found to diverge at the base of the A. carterae clade (Figs. 9 and 10). The two A. cf. massartii strains from Tasmania were found to form a sister group to the A. carterae clades, whereas the other two strains were a sister group to A. carterae and the other two A. massartii ...
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... analysis based on partial LSU rDNA. The phylogenetic analyses based on partial LSU rDNA using BA (Fig. 9) and ML (Fig. 10) resulted in trees with similar topologies. In both analyses, most branches were very well supported by either boot- strap analysis (Fig. 10) or high posterior probability (PP) values (Fig. 9). The main difference between the two analyses was in the sister-group relation- ship of the clade containing A. carterae, A. massartii, A. gibbosum, and A. trulla. In the BA analysis, this clade was found to be the sister group to the clade containing A. steinii, A. mootonorum, and A. herdmanii ( Fig. 9), whereas in the analysis using ML, this clade was found to be the sister group to A. operculatum (Fig. 10). In both phylogenetic analyses, the species A. steinii, A. operculatum, A. gibbosum, A. carterae, and A. trulla formed clades that were clearly separated from one another ( Figs. 9 and 10). Within these clades, some variation was found, with A. steinii strains differing from each other by 0.5%, excluding the hypervariable D2 region, and A. operculatum strains differing by 0- 1.0% (Table 3). The species A. carterae formed a clade, but within that three distinct clades were found that differed from each other by about 40 fixed base differences (up to 1.7% excluding the D2 region) (Figs. 9 and 10, Table 3). The strains of A. massartii did not form a single clade. In both analyses, two lineages of A. massartii were found to diverge at the base of the A. carterae clade (Figs. 9 and 10). The two A. cf. massartii strains from Tasmania were found to form a sister group to the A. carterae clades, whereas the other two strains were a sister group to A. carterae and the other two A. massartii ...
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... analysis based on partial LSU rDNA. The phylogenetic analyses based on partial LSU rDNA using BA (Fig. 9) and ML (Fig. 10) resulted in trees with similar topologies. In both analyses, most branches were very well supported by either boot- strap analysis (Fig. 10) or high posterior probability (PP) values (Fig. 9). The main difference between the two analyses was in the sister-group relation- ship of the clade containing A. carterae, A. massartii, A. gibbosum, and A. trulla. In the BA analysis, this clade was found to be the sister group to the clade containing A. steinii, A. mootonorum, and A. herdmanii ( Fig. 9), whereas in the analysis using ML, this clade was found to be the sister group to A. operculatum (Fig. 10). In both phylogenetic analyses, the species A. steinii, A. operculatum, A. gibbosum, A. carterae, and A. trulla formed clades that were clearly separated from one another ( Figs. 9 and 10). Within these clades, some variation was found, with A. steinii strains differing from each other by 0.5%, excluding the hypervariable D2 region, and A. operculatum strains differing by 0- 1.0% (Table 3). The species A. carterae formed a clade, but within that three distinct clades were found that differed from each other by about 40 fixed base differences (up to 1.7% excluding the D2 region) (Figs. 9 and 10, Table 3). The strains of A. massartii did not form a single clade. In both analyses, two lineages of A. massartii were found to diverge at the base of the A. carterae clade (Figs. 9 and 10). The two A. cf. massartii strains from Tasmania were found to form a sister group to the A. carterae clades, whereas the other two strains were a sister group to A. carterae and the other two A. massartii ...
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... analysis based on partial LSU rDNA. The phylogenetic analyses based on partial LSU rDNA using BA (Fig. 9) and ML (Fig. 10) resulted in trees with similar topologies. In both analyses, most branches were very well supported by either boot- strap analysis (Fig. 10) or high posterior probability (PP) values (Fig. 9). The main difference between the two analyses was in the sister-group relation- ship of the clade containing A. carterae, A. massartii, A. gibbosum, and A. trulla. In the BA analysis, this clade was found to be the sister group to the clade containing A. steinii, A. mootonorum, and A. herdmanii ( Fig. 9), whereas in the analysis using ML, this clade was found to be the sister group to A. operculatum (Fig. 10). In both phylogenetic analyses, the species A. steinii, A. operculatum, A. gibbosum, A. carterae, and A. trulla formed clades that were clearly separated from one another ( Figs. 9 and 10). Within these clades, some variation was found, with A. steinii strains differing from each other by 0.5%, excluding the hypervariable D2 region, and A. operculatum strains differing by 0- 1.0% (Table 3). The species A. carterae formed a clade, but within that three distinct clades were found that differed from each other by about 40 fixed base differences (up to 1.7% excluding the D2 region) (Figs. 9 and 10, Table 3). The strains of A. massartii did not form a single clade. In both analyses, two lineages of A. massartii were found to diverge at the base of the A. carterae clade (Figs. 9 and 10). The two A. cf. massartii strains from Tasmania were found to form a sister group to the A. carterae clades, whereas the other two strains were a sister group to A. carterae and the other two A. massartii ...
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... analysis based on partial LSU rDNA. The phylogenetic analyses based on partial LSU rDNA using BA (Fig. 9) and ML (Fig. 10) resulted in trees with similar topologies. In both analyses, most branches were very well supported by either boot- strap analysis (Fig. 10) or high posterior probability (PP) values (Fig. 9). The main difference between the two analyses was in the sister-group relation- ship of the clade containing A. carterae, A. massartii, A. gibbosum, and A. trulla. In the BA analysis, this clade was found to be the sister group to the clade containing A. steinii, A. mootonorum, and A. herdmanii ( Fig. 9), whereas in the analysis using ML, this clade was found to be the sister group to A. operculatum (Fig. 10). In both phylogenetic analyses, the species A. steinii, A. operculatum, A. gibbosum, A. carterae, and A. trulla formed clades that were clearly separated from one another ( Figs. 9 and 10). Within these clades, some variation was found, with A. steinii strains differing from each other by 0.5%, excluding the hypervariable D2 region, and A. operculatum strains differing by 0- 1.0% (Table 3). The species A. carterae formed a clade, but within that three distinct clades were found that differed from each other by about 40 fixed base differences (up to 1.7% excluding the D2 region) (Figs. 9 and 10, Table 3). The strains of A. massartii did not form a single clade. In both analyses, two lineages of A. massartii were found to diverge at the base of the A. carterae clade (Figs. 9 and 10). The two A. cf. massartii strains from Tasmania were found to form a sister group to the A. carterae clades, whereas the other two strains were a sister group to A. carterae and the other two A. massartii ...

Citations

... It has long been suspected that the defi nition does not mirror its phylogeny (Daugbjerg et al., 2000;Saldarriaga et al., 2001), but a later emendation of the genus defi nition was performed after reinvestigation of A . operculatum Claparède & Lachmann, the type species of Amphidinium , as well as putative relatives of dozens of Amphidinium taxa units Murray et al., 2004). The genus Amphidinium sensu stricto now only includes those athecate benthic or endosymbiotic dinofl agellates with minute irregular triangular-or crescent-shaped epicones that are defl ected towards the left . ...
... The genus Amphidinium sensu stricto now only includes those athecate benthic or endosymbiotic dinofl agellates with minute irregular triangular-or crescent-shaped epicones that are defl ected towards the left . Species that do not fi t the criteria for the genus as redefi ned Murray et al., 2004), but have not yet been investigated to determine the generic affi nities, are classifi ed as Amphidinium sensu lato (Hoppenrath et al., 2014). A variety of morphological features have been used to identify Amphidinium species, including the cell size and shape, the nucleus location and shape, the presence, location, and number of pusules, pyrenoids, chloroplasts, eyespots, scales, as well as life cycle stages (Claparède and Lachmann, 1859;Taylor, 1971;Maranda and Shimizu, 1996;Steidinger and Tangen, 1997;Sekida et al., 2003). ...
... A variety of morphological features have been used to identify Amphidinium species, including the cell size and shape, the nucleus location and shape, the presence, location, and number of pusules, pyrenoids, chloroplasts, eyespots, scales, as well as life cycle stages (Claparède and Lachmann, 1859;Taylor, 1971;Maranda and Shimizu, 1996;Steidinger and Tangen, 1997;Sekida et al., 2003). However, there are no unambiguous features that can be used to diff erentiate Amphidinium species, and some characters can even overlap among species (Murray and Patterson, 2002;Jørgensen et al., 2004;Murray et al., 2004). Therefore, a combination of characters seems to be the best approach to diff erentiate Amphidinium species (Karafas et al., 2017). ...
Article
Amphidinium species are amongst the most abundant benthic dinoflagellates in marine intertidal sandy ecosystems. Some of them are able to produce a variety of bioactive compounds that can have both harmful effects and pharmaceutical potentials. The diversity of Amphidinium in shallow waters along the Chinese coast was investigated by isolating single cells from sand, coral, and macroalgal samples collected from 2012 to 2020. Their morphologies were subjected to examination using light microscopy (LM) and scanning electron microscopy (SEM). A total of 74 Amphidinium strains were morphologically identified, belonging to 11 species: A. carterae, A. gibbosum, A. operculatum, A. massartii, A. cf. massartii, A. fijiensis, A. pseudomassartii, A. steinii, A. thermaeum, A. theodori, A. tomasii, as well as an undefined species. The last seven species have not been previously reported in Chinese waters. Amphidinium carterae subclades I, II, and IV were found in the South China Sea, while subclade III was only found in the Yellow Sea. Threadlike body scales were observed on the surface of subclades III and V, supporting the idea that A. carterae might contain several different species. Large subunit ribosomal RNA (LSU rRNA) sequences-based phylogeny revealed two groups (Groups I and II) within Amphidinium, which is consistent with the relative position of sulcus (in touch with cingulum or not). In addition, large differences in morphology and molecular phylogeny between A. operculatum (the type species of Amphidinium) and other species, suggest that a subdivision of Amphidinium might be needed. The pigment profiles of all available strains were analyzed by high performance liquid chromatography (HPLC). Eleven pigments, including peridinin, diadinoxanthin, diatoxanthin, pheophorbide (and pheophorbide a), antheraxanthin, β-carotene, and four different chlorophylls were detected. The high pheophorbide/pheophorbide a ratio in Amphidinium implies that it may be a good candidate as a natural source of photosensitizers, a well-known anticancer drug.
... Example of genera where sequence-guided approaches have been widely applied include the following: Amphidinium, a genus displaying limited morpho-diversity and cryptic speciation, now shown using molecular data to contain at least 18 species (e.g. Murray et al., 2004Murray et al., , 2012Karafas et al., 2017); Gambierdiscus, initially represented by a single species (G. toxicus), but now containing 20 species largely distinguished using sequence data (e.g., Litaker et al., 2009;Kretzschmar et al., 2017Kretzschmar et al., , 2019; Karenia (e.g., De Salas et al., 2004a,b;Haywood et al., 2004) established with three species in 2000, but now containing at least 12 species; Karlodinium, a genus considered to contain potentially 3 species when established, but now containing 16 species (e.g., De Salas et al., 2008); Takayama, established with four species using sequence-guided principles (De Salas et al., 2003), now containing seven species; distinguishing cryptic species among the smaller members of Phalacroma (Daugbjerg et al., 2019); and the microreticulate cyst group of Gymnodinium species (Bolch et al., 1999;Gu et al., 2013) highlighted in further detail in the case study. ...
Chapter
Dinoflagellates are a functionally diverse group of organisms, rich in morphological complexity and features, that has formed the basis of a well-developed classical taxonomy. Their extensive fossil record of resistant resting stages (dinocysts) is unique among protists and has supported a comparatively early development of detailed evolutionary theories to explain their apparent morphological diversity. This chapter presents a historical perspective of the application and impact of molecular approaches on the taxonomy, systematics, and phylogenetic theory of dinoflagellates. Application of molecular approaches are described as overlapping phases, beginning in the 1980s with early investigations of DNA structure and phylogenetic affinities among other protists; followed by four phases of molecular-driven discovery: (I) Challenging existing evolutionary theories; (II) Discovering widespread cryptic diversity; (III) Increased taxon and gene sampling; and (IV) Technology-accelerated diversity discovery. Current hurdles to all-of community molecular identification are discussed, and the potential of integrated molecular, fluidics, and imaging to enable high-throughput single-cell ‘omics and identity-linked molecular data for dinoflagellate taxonomy.
... Therefore, significant attention has been paid to the role of microphy-cycle stage, and body scales morphology (Claparède and Lachmann 1859, Maranda and Shimizu 1996, Sekida et al. 2003. However, there are no unambiguous features that can be used to differentiate Amphidinium sensu stricto species, and some characteristics can even overlap among species (Murray and Patterson 2002, Jørgensen et al. 2004b, Murray et al. 2004). Body scale possess or not as well as the morphology of it is a useful diagnostic characterization. ...
... Additional types of body scales could be expected with more detailed morphological investigation of both Amphidinium sensu stricto and the large number of Amphidinium sensu lato species. The location of longitudinal flagellum is also considered an important diagnostic characterization (Jørgensen et al. 2004b, Murray et al. 2004, Karafas et al. 2017. Three groups within Amphidinium sensu stricto, which show consistency with regards to their lower, anterior, and middle third of the cell positioning of longitudinal flagellum insertion, have been identified. ...
... Three groups within Amphidinium sensu stricto, which show consistency with regards to their lower, anterior, and middle third of the cell positioning of longitudinal flagellum insertion, have been identified. However, such division was not supported by rRNA-based phylogeny, and the relationship among different groups still need to be determined (Murray et al. 2004, Karafas et al. 2017. In brief, a combination of characteristics seems to be the best approach to differentiate Amphidinium species (Karafas et al. 2017). ...
Article
Amphidinium species are amongst the most abundant benthic dinoflagellates in marine intertidal sandy ecosystems. Some of them produce a variety of bioactive compounds that have both harmful effects and pharmaceutical potential. In this study, Amphidinium cells were isolated from intertidal sand collected from the East China Sea. The two strains established were subjected to detailed examination by light, and scanning and transmission electron microscopy. The vegetative cells had a minute, irregular, and triangular-shaped epicone deflected to the left, thus fitting the description of Amphidinium sensu stricto. These strains are distinguished from other Amphidinium species by combination characteristics: (1) longitudinal flagellum inserted in the lower third of the cell; (2) icicle-shaped scales, 276 ± 17 nm in length, on the cell body surface; (3) asymmetrical hypocone with the left side longer than the right; and (4) presence of immotile cells. Therefore, they are described here as Amphidinium stirisquamtum sp. nov. The molecular tree inferred from small subunit rRNA, large subunit rRNA, and internal transcribed spacer-5.8S sequences revealed that A. stirisquamtum is grouped together with the type species of Amphidinium, A. operculatum, in a fully supported clade, but is distantly related to other Amphidinium species bearing body scale. Live A. stirisquamtum cells greatly affected the survival of rotifers and brine shrimp, their primary grazers, making them more susceptible to predation by the higher tropic level consumers in the food web. This will increase the risk of introducing toxicity, and consequently, the bioaccumulation of toxins through marine food webs.
... The authors measured average and running velocities for the cell and also the velocity of travelling waves along the cell for several media with different viscosities and at different temperatures. [73,228] PLOS 39/73 [ 147,236] Haloarcula quadrata [ [247][248][249] Apedinella spinifera [279] ...
Preprint
Unicellular microscopic organisms living in aqueous environments outnumber all other creatures on Earth. A large proportion of them are able to self-propel in fluids with a vast diversity of swimming gaits and motility patterns. In this paper we present a biophysical survey of the available experimental data produced to date on the characteristics of motile behaviour in unicellular microswimmers. We assemble from the available literature empirical data on the motility of four broad categories of organisms: bacteria (and archaea), flagellated eukaryotes, spermatozoa and ciliates. Whenever possible, we gather the following biological, morphological, kinematic and dynamical parameters: species, geometry and size of the organisms, swimming speeds, actuation frequencies, actuation amplitudes, number of flagella and properties of the surrounding fluid. We then organise the data using the established fluid mechanics principles for propulsion at low Reynolds number. Specifically, we use theoretical biophysical models for the locomotion of cells within the same taxonomic groups of organisms as a means of rationalising the raw material we have assembled, while demonstrating the variability for organisms of different species within the same group. The material gathered in our work is an attempt to summarise the available experimental data in the field, providing a convenient and practical reference point for future studies.
... Interestingly, Karafas et al. (2017) recently described six new Amphidinium species based on morphological and molecular phylogenetic analyses. The description of A. massartii in the present study agrees with that of Karafas et al. (2017) and Murray et al. (2004), who observed distinctive characteristics like the presence of a single plastid superficially located, and a narrow epicone. The LSU rDNA sequence of the strain Am-Cub-1 was closely related with the strain TM16, clustering in the clade I of A. massartii in Karafas et al. (2017), which confirms its identification. ...
... Finally, the morphometric data reported herein for A. operculatum agree with those described for this species by Hoppenrath et al. (2014). The analysis of LSU rDNA sequences of strains Ao-Ecpb-1 and Ao-Rec-1 confirmed the identification as A. operculatum, a common species distributed worldwide (Murray et al. 2004;Saburova et al. 2009;Hoppenrath et al. 2014). ...
... The differences in maximum cell density and growth rates between A. operculatum strains from the ECPB (92.5 × 10 3 cells mL −1 and 0.26 day −1 , respectively) and Recife (33.9 × 10 3 cells mL −1 and 0.19 day −1 , respectively) highlight intraspecific differences showed in previous studies with strains of Amphidinium genus (Murray et al. 2004). In fact, most strains attaining high cell yields were isolated from the ECPB, such as A. operculatum and Prorocentrum sp. ...
Article
Full-text available
The present study investigated selected benthic dinoflagellates isolated from different regions from the Western Atlantic, with respect to their morphology, growth, toxicity, and toxin production in culture. A total of nine strains of benthic dinoflagellates belonging to three genera were cultivated: Amphidinium massartii, Amphidinium operculatum (2 strains), Coolia malayensis (2 strains), Prorocentrum hoffmannianum (2 strains), and Prorocentrum mexicanum, whose morphological and genetic characterizations matched previous descriptions, and Prorocentrum sp., morphologically related to P. cf. norrissianum. The two strains of C. malayensis from Brazil attained the highest growth rates (0.42–0.47 day⁻¹), but the lowest cell densities (2.2–2.9 × 10⁴ cells mL⁻¹) in culture. The highest cell densities were recorded for A. massartii from Cuba (3.8 × 10⁵ cells mL⁻¹). All species/strains investigated exhibited moderate toxicity to larvae of the brine shrimp Artemia salina; A. massartii being the most toxic species and Prorocentrum sp. the least one. Additionally, extracts of Prorocentrum species (P. hoffmannianum and Prorocentrum sp.) tested positive in mouse bioassays following intraperitoneal injection. Moderate to high concentrations of okadaic acid (OA), but no dinophysistoxins (DTXs), were found in both P. hoffmannianum strains from Cuba; but no diarrheic toxins were detected in either P. mexicanum from Cuba or Prorocentrum sp. from southern Brazil. Finally, five novel amphidinols were detected in cultures of both A. massartii (Cuba) and A. operculatum (Brazil) by LC-MS/MS, with molecular weights of 1440.8 (two isomers), 1360.8, 1287.7, and 984.6. These findings clearly indicate the need to include benthic species among the harmful microalgae surveyed in regional monitoring programs of phytoplankton.
... ovata, Ostreopsis cf. siamensis, Prorocentrum lima, Prorocentrum rhathymum, Prorocentrum concavum and Amphidinium carterae), while the possible toxicity of Coolia monotis, Prorocentrum emarginatum and Amphidinium operculatum needs more investigations (Murray et al., 2004;Ignatiades and Gotsis-Skretas, 2010;Hoppenrath et al., 2014). ...
Article
Harmful events associated with epibenthic dinoflagellates, have been reported more frequently over the last decades. Occurrence of potentially toxic benthic dinoflagellates, on the leaves of two magnoliophytes (Cymodocea nodosa and Zostera noltei) and thalli of the macroalgae (Ulva rigida), was monitored over one year (From May 2015 to April 2016) in the Bizerte Bay and Lagoon (North of Tunisia, Southern Mediterranean Sea). The investigated lagoon is known to be highly anthropized. This is the first report on the seasonal distribution of epibenthic dinoflagellates hosted by natural substrates, from two contrasted, adjacent coastal Mediterranean ecosystems. The environmental factors promoting the development of the harmful epibenthic dinoflagellates Ostreopsis spp., Prorocentrum lima and Coolia monotis were investigated. The highest cell densities were reached by Ostreopsis spp. (1.9 × 103 cells g-1 FW, in October 2015), P. lima (1.6 × 103 cells g-1 FW, in June 2015) and C. monotis (1.1 × 103 cells g-1 FW, in May 2015). C. nodosa and Z. noltei were the most favorable host macrophytes for C. monotis (in station L2) and Ostreopsis spp. (in station L3), respectively. Positive correlations were recorded between Ostreopsis spp. and temperature. Densities of the epibenthic dinoflagellates varied according to the collection site, and a great disparity was observed between the Bay and the Lagoon. Maximum concentrations were recorded on C. nodosa leaves from the Bizerte Bay, while low epiphytic cell abundances were associated with macrophytes sampled from the Bizerte Lagoon. The observed differences in dinoflagellate abundances between the two ecosystems (Bay-Lagoon) seemed not related to the nutrients, but rather to the poor environmental conditions in the lagoon.
... During the bloom event that occurred in January 2015 no fish kills were reported. Among benthic diatoms, the tychoplanktonic centric species Asteromphalus arachne (Brébisson) Ralfs in Pritchard 1861 (Fig. 5D) Amphidinium carterae is abundant and ubiquitous in diverse marine environments and widely distributed in tropical, subtropical and temperate waters (Hulburt, 1957;Taylor, 1971;Dodge, 1982;Sampayo, 1985;Larsen and Petersen, 1990;Murray and Patterson, 2002;Murray et al., 2004Murray et al., , 2015Larsen and Nguyen, 2004;Echigoya et al., 2005;Gárate-Lizárraga, 2012;Omura et al., 2012;Seoane et al., 2018). The identification of Amphidinium at the species level is difficult in some cases because of shared morphological characteristics. ...
... Some cells became rounded or they enlarged when they were swimming. This cell plasticity or 'metabolic movement' has been previously mentioned for various Amphidinium species (Massart, 1920;Anissimowa, 1926;Barlow and Triemer, 1988;Maranda and Shimizu, 1996;Murray et al., 2004). Such observations enhance the view that this trait could be typical for the genus (Dolapsakis and Economou-Amilli, 2009). ...
Article
Monthly phytoplankton samples were collected from January 2013 to December 2015 at a fixed sampling site in Bahía de La Paz, Gulf of California. During this study 26 samplings were Amphidinium cf. carterae positive. The highest densities of A. cf. carterae (754.2×103 to 1022.4×103 cells L−1) were recorded during a bloom detected in January 2015 when water temperatures were 20–22 °C. This dinoflagellate showed a well-marked seasonal variation, being found mainly from November to April. Blooms of the species were linked to the upwelled water due to the northwesterly wind. Cysts surrounded by a mucilaginous membrane of A. cf. carterae were found. We also observed these hyaline cysts inside zooplankton fecal pellets. Other benthic/tychoplanktonic dinoflagellates and diatoms, including some potentially toxic species were also found. The occurrence of blooms of A. cf. carterae in Bahía de La Paz could represent a risk for aquaculture activities and human health.
... Vegetative cells are generally dorsoventrally compressed with a minute, triangular or crescent-shaped, usually left-deflected epicone. The type species of the genus, A. operculatum, was re-described, and the genus was redefined; based on morphological and molecular phylogenetic analyses, six distinct species were identified ( Jørgensen et al., 2004;Murray et al., 2004). Furthermore, the genus Prosoaulax Calado & Moestrup was erected for some freshwater species previously ascribed to Amphidinium (Calado and Moestrup, 2005). ...
Article
Full-text available
Many benthic dinoflagellates are known or suspected producers of lipophilic polyether phycotoxins, particularly in tropical and subtropical coastal zones. These toxins are responsible for diverse intoxication events of marine fauna and human consumers of seafood, but most notably in humans, they cause toxin syndromes known as diarrhetic shellfish poisoning (DSP) and ciguatera fish poisoning (CFP). This has led to enhanced, but still insufficient, efforts to describe benthic dinoflagellate taxa using morphological and molecular approaches. For example, recently published information on epibenthic dinoflagellates from Mexican coastal waters includes about 45 species from 15 genera, but many have only been tentatively identified to the species level, with fewer still confirmed by molecular criteria. This review on the biodiversity and biogeography of known or putatively toxigenic benthic species in Latin America, restricts the geographical scope to the neritic zones of the North and South American continents, including adjacent islands and coral reefs. The focus is on species from subtropical and tropical waters, primarily within the genera Prorocentrum, Gambierdiscus/Fukuyoa, Coolia, Ostreopsis and Amphidinium. The state of knowledge on reported taxa in these waters is inadequate and time-series data are generally lacking for the prediction of regime shift and global change effects. Details of their respective toxigenicity and toxin composition have only recently been explored in a few locations. Nevertheless, by describing the specific ecosystem habitats for toxigenic benthic dinoflagellates, and by comparing those among the three key regions - the Gulf of Mexico, Caribbean Sea and the subtropical and tropical Pacific coast, insights for further risk assessment of the global spreading of toxic benthic species is generated for the management of their effects in Latin America.
... They included A. boggayum, A. carterae, A. massartii, A. mootonorum and A. thermaeum. The type specimen of A. trulla was isolated from seawater in Rangaunu Harbour, but the cells have been described as benthic in Australia ( Murray et al. 2004). Many antifungal and haemolytic amphidinol analogues have been isolated from an A. carterae isolate from New Zealand and their structures characterised (Houdai et al. 2001;Echigoya et al. 2005). ...
Article
New Zealand benthic and epiphytic dinoflagellate records increased in recent years as harmful algal bloom research increased. This was largely due to risk assessments of micro-algal biotoxins for the seafood industry and concerns regarding ciguatera fish poisoning in humans from toxic finfish. High-throughput sequencing enabled the detection of dinoflagellate species that were previously overlooked by microscopy, particularly where diatoms or sediments obscured visual identification. This checklist includes new species records for New Zealand and species usually considered planktonic, but which have benthic life stages. Thirty-one dinoflagellate genera were recorded from isolations and descriptions of living cells: Alexandrium, Amphidinium, Archaeperidinium, Azadinium, Biecheleria, Blastodinium, Bysmatrum, Coolia, Crypthecodinium, Cryptoperidiniopsis, Durinskia, Ensiculifera, Fukuyoa, Gambierdiscus, Gymnodinium, Gyrodinium, Heterocapsa, Karenia, Kryptoperidinium, Ostreopsis, Pelagodinium, Pentapharsodinium, Pfiesteria, Polarella, Prorocentrum, Protodinium, Protoperidinium, Pseudopfiesteria, Scrippsiella, Togula and Vulcanodinium. A further nine genera were detected by high-throughput sequencing: Cachonina, Dinophysis, Fragilidium, Gonyaulax, Karlodinium, Lepidodinium, Protodinium, Symbiodinium and Woloszynskia.
... The measured dimensions ranged from 10.04 to 12.86 mm in length and 8.36-10.98 mm in width, that are in line with those reported for this species [2,3]. ...
Article
Full-text available
We present the data corresponding to the isolation and morphological and molecular characterization of a strain of Amphidinium carterae, isolated in Mallorca Island waters and now deposited in the microalgae culture collection of the Plant Biology and Ecology Department of the University of the Basque Country under the reference Dn241Ehu. The morphological characterization was made using two different techniques of microscopy and the molecular characterization by using the 28S rDNA sequences of D1 and D2 domains. This strain has been used for a culture study in an indoor LED-lighted pilot-scale raceway to determine its production of carotenoids and fatty acids, “Long-term culture of the marine dinoflagellate microalga Amphidinium carterae in an indoor LED-lighted raceway photobioreactor: Production of carotenoids and fatty acids.” (Molina-Miras et al., 2018) [1].