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Ecology

provided by NMNH Marine Dinoflagellates
Dinophysis sacculus is a planktonic species (Taylor et al. 1995). Blooms have been reported from Portugal, North Atlantic Ocean (Alvito et al. 1990; Sampayo et al. 1990), and Italy, Mediterranean Sea (Zingone et al. 1998).
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Etymology

provided by NMNH Marine Dinoflagellates
Sacculus' (Latin) refers to the sack-like shape of the hypotheca.
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Habitat and Locality

provided by NMNH Marine Dinoflagellates
D. sacculus is distributed widely in cold and temperate waters (Taylor et al. 1995), most often observed in semi-enclosed basins, estuaries and lagoons (Zingone et al. 1998). Populations have mostly been reported from the Mediterranean Sea (Zingone et al. 1998), with a few reports from the Atlantic Ocean (Murray & Whitting 1900; Cleve 1900; 1902).
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Morphology and Structure

provided by NMNH Marine Dinoflagellates
D. sacculus is most likely a photosynthetic species; Larsen and Moestrup (1992) state that 'chloroplasts are probably present'. Moreover, Giacobbe (1995) found the possible presence of chlorophyll and phycobilin pigments in using epifluorescence microscopy. Giacobbe and Gangemi (1997) have shown that the concavity of the dorsal margin can vary in the life history of the species; e.g. the development of the megacytic zone. This area can increase before cell division or following gamete fusion (Giacobbe & Gangemi 1997). Biological factors (i.e. life history and nutrition) can explain the presence of different morphotypes in the same locality (Zingone et al. 1998).
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Nomenclatural Types

provided by NMNH Marine Dinoflagellates
Holotype: Dinophysis sacculus Stein, 1883: plate 20, fig. 10
Type Locality: Mediterranean Sea: Adriatic Sea, Quarnero, Italy
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Remarks

provided by NMNH Marine Dinoflagellates
D. sacculus has a history wrought with identification problems mainly attributable to the morphological variability of this species. This problem is enhanced by the many synonyms and questionable identifications that have accumulated in the literature over the years (see Zingone et al. 1998).
Many authors consider Phalacroma to be synonymous with Dinophysis (Steidinger & Tangen 1996).
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Reproduction

provided by NMNH Marine Dinoflagellates
D. sacculus reproduces asexually by binary fission (Taylor et al., 1995). Giacobbe and Gangemi (1997) reported sexual reproduction in this species.
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cc-publicdomain
bibliographic citation
Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Species Comparison

provided by NMNH Marine Dinoflagellates
D. sacculus is most often misidentified as D. acuminata. The major difference between these two species is the shape of the large hypothecal plates: in D. sacculus they are long and sack-like, whereas in D. acuminata they are shorter, more convex dorsally and often more slender posteriorly. D. acuminata also exhibits more pronounced thecal areolation and sulcal list ornamentation, but these are variable characteristics. Moreover, since D. sacculus and D. acuminata rarely occur in the same area with the same importance, the possibility of misidentification is reduced (Zingone et al. 1998). Surface thecal ornamentation in this species is similar to a number of other Dinophysis species: D. acuta, D. caudata, D. norvegica and D. fortii (Hallegraeff & Lucas 1988).
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bibliographic citation
Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Species Overview

provided by NMNH Marine Dinoflagellates
Dinophysis sacculus is an armoured, marine, planktonic dinoflagellate species. It is a toxic species associated with DSP outbreaks in Europe.
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bibliographic citation
Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Synonyms

provided by NMNH Marine Dinoflagellates
Dinophysis reniformis Schröder, 1906
Dinophysis pavillardii Schröder, 1906
Dinophysis ventrecta Schiller, 1933
Dinophysis phaseolus Silva, 1952
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Taxonomic Description

provided by NMNH Marine Dinoflagellates
Species in this genus are laterally compressed with a small, cap-like epitheca and a much larger hypotheca (dorso-ventral depth of epitheca is 1/3 to 1/2 hypotheca). The shape of the cell in lateral view is the most important criterion used for identification (Taylor et al. 1995). Cells of Dinophysis sacculus are long and oval with a rounded posterior (Figs. 1-5). It is typically sack-like in shape and highly variable in width. A short left sulcal list (about 1/2 length of the cell) extends midway down the hypotheca (Figs. 1, 2). Occasionally cells are found with a few small blunt spines on the posterior end (Figs. 1, 3, 4, 6) (Larsen & Moestrup 1992; Taylor et al. 1995; Zingone et al. 1998). The thecal surface is covered with small unevenly distributed pores; however, the surface texture can vary from completely smooth (Fig. 3) to coarsely areolate (Figs. 1, 2, 4). Pores are not found in the megacytic zone (Fig. 3). Cell size ranges: 40-60 µm in length and 20-40 µm in width (Larsen & Moestrup 1992; Taylor et al. 1995; Zingone et al. 1998).
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bibliographic citation
Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Thecal Plate Description

provided by NMNH Marine Dinoflagellates
The small epitheca is made up four plates nearly totally obscured by the well-developed cingular lists. The cingulum is bordered by two cingular lists: a wide anteriorly projected anterior cingular list (ACL), and a smooth posterior cingular list (PCL) (Figs. 1-3) (Zingone et al. 1998). The sulcus is comprised of four irregularly shaped plates. The flagellar pore is housed in the sulcal area. The left sulcal list generally reaches the middle of the cell, however, the length can vary (Figs. 1-3). Three strong supporting sulcal ribs are thin and smooth, and in general, are without ornamentation (Figs. 1, 4-6). The right sulcal list is also visible (Fig. 2)(Zingone et al. 1998). The large hypotheca is made up of four plates. The dorsal and ventral margins of the hypotheca are important morphological characteristics used to identify this species (Zingone et al. 1998). The dorsal margin is straight or undulating: convex below the cingulum, slightly concave in the middle, and convex again posteriorly (Figs. 1, 3). The ventral margin also displays some undulation: convex at the middle, and concave below the middle (Figs. 1, 6). The shape of these margins is also variable in this species. The convexity of the ventral margin generally corresponds to the region where the third rib of the left sulcal list is inserted (Taylor et al. 1995).
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cc-publicdomain
bibliographic citation
Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Toxicity

provided by NMNH Marine Dinoflagellates
D. sacculus has been found to produce okadaic acid (OA) (Masselin et al. 1992; Giacobbe et al. 1995; Delgado et al. 1996). It has been linked to diarrhetic shellfish poisoning (DSP) occurrences along the Mediterranean and Atlantic European coasts (Alvito et al. 1990; Sampayo et al. 1990; Lassus & Marcaillou-Le Baut 1991; Belin 1993; Boni et al. 1993; Marasovic et al. 1998).
license
cc-publicdomain
bibliographic citation
Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).