Smithsonian Marine Station at Fort Pierce

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Figure 1.Schematic drawing of Amphidinium carterae.

Figure 2. Amphidinium carterae from the boat basin of Harbor Branch Oceanographic Institute. Fort Pierce, FL. September 2007.

Figure 3. Amphidinium carterae from clone SMS-20, isolated from an aquarium tank at the Smithsonian Marine Ecosystems Exhibit. Fort Pierce, FL. Summer 2009.

Species Name: Amphidinium carterae Hulburt
Common Name: None
Synonymy: Amphidinium klebsii, sensu Carter (non Kofoid & Swezy)
Amphidinium microcephalum Norris
Amphidinium carteri Hulburt (orthographic synonym)

    Kingdom Phylum/Division Class: Order: Family: Genus:
    Protista Dinophyta Dinophyceae Gymnodiniales   Amphidinium

    Use your mouse to rollover the terms in purple for their definitions. If this feature is not supported by your browser, please refer to the accompanying glossary for terminology.

    Species Description

    As with others of the genus, the epicone is smaller than the hypocone (Figures 1 & 2). The cell is dorso-ventrally flattened, and oval in ventral view. The epicone is asymmetric, somewhat crescent or tongue shaped, and pointed toward the left side.  The hypocone is elliptical with a slight convex right margin, a mostly straight left margin, and a smoothly rounded antapex. The anterior flagellum encircles the cell in the cingulum, which is V-shaped and higher on the dorsal side. The posterior flagellum extends beyond the cell posteriorly, up to 1.5 times the body length (Figures 2 & 3). The nucleus is flattened, often slightly curved, and confined to the lower part of the hypocone.

    Potentially Misidentified Species

    Although there is some resemblance to A. klebsii, Amphidinium carterae has only one chloroplast, multilobed, with a central pyrenoid (Figure 1); while A. klebsii is twice as large and has multiple small chloroplasts radiating from a central pyrenoid. The validity of these distinctions was examined by Murray and Patterson (2004). According to Dodge (1982), A. klebsii is a later synonym of A. operculatum Claparede & Lachman.


    Habitat & Regional Occurence

    Amphidinium carterae is nominally a benthic or epiphytic species, although it is commonly found in the plankton from boreal regions through the tropics in coastal waters and estuaries. Most reports are from coasts of the Atlantic and Pacific oceans.  It has been recorded from the Arctic Ocean (Okolodkov 1998), and as an endosymbiont in the Scyphozoan jellyfish Cassiopeia xamachana (Murray et al. 2004).

    Indian River Lagoon Distribution

    his species occurs throughout the IRL, but has not been verified from the Mosquito Lagoon or Banana River.


    Size & Abundance

    Cells are 12-18 µm in length, and 8-10 µm wide. Some literature reports give a wider range of sizes, but there may be confusion with similar species such as A. operculatum. Although blooms of as much as 107 cells per liter have been reported (Baig et al. 2006), such densities are unusual. In the IRL, several thousands of cells per liter are not uncommon (Figure 3 & Video).


    Cao Vien (1967) reported sexual cysts in a culture of this species (i.e. hypnozygotes), but this has yet to be independently confirmed. Asexual reproduction is by fission.


    Amphidinium carterae has long been recognized as a producer of powerful ichthyotoxins and hemolytic substances (Tindall & Morton 1998; Echigoya et al. 2005). It has a variety of detrimental effects on adults and larvae of a number of invertebrates, and is implicated as a causative agent in human ciguatera (Baig et al. 2006). The ichthyotoxin Carteraol-E (Huang et al. 2009) was shown to have antifungal activity. Although it has not been implicated as causing problems in the IRL, the issue is complicated. Similarity in morphology to other species (Joergensen et al. 2004; Dolapsakis & Economou-Amilli 2009), insufficient monitoring activity for potential harmful effects, and genotypic variability within the species (Murray et al. 2004) suggests that there are both toxic and nontoxic strains. To date, confirmation of these toxins has not been shown for IRL strains of the species.


    No information is available at this time


    No information is available at this time


    No information is available at this time


    Baig, HS, Saifullah, SM & A Dar. 2006. Occurrence and toxicity of Amphidinium carterae Hulburt in the North Arabian Sea. Harmful Algae 5: 133-140.

    Cao Vien, M. 1967. Sur l’existence de phénomènes sexuels chez un Péridinien libre, l’Amphidinium carteri. Comptes rendus des séances de l’Académie des sciences, Paris, Série D 264: 1006-1008.

    Carter, N. 1937. New or interesting algae from brackish water. Archiv für Protistenkunde 90: 1-68.

    Dolapsakis, NP & A Economou-Amilli. 2009. A new marine species of Amphidinium (Dinophyceae) from Thermaikos Gulf, Greece. Acta Protozoologica 48: 153-170.

    Echigoya, R, Rhodes, L, Oshima, Y & M Satake. 2005. The structures of five new antifungal and hemolytic amphidinol analogs from Amphidinium carterae collected in New Zealand. Harmful Algae 4: 383-389.

    Huang, S, Kuo, C, Lin, Y, Chen, Y & C Lu. 2009. Carteraol E, a potent polyhydroxyl ichthyotoxin from the dinflagellate Amphidinium carterae. Tetrahedron Letters 50: 2512-2515.

    Hulburt, EM. 1957. The taxonomy of unarmored Dinophyceae of shallow embayments on Cape Cod, Massachusetts. Biol. Bull. 112: 196-219.

    Joergensen, MF, Murray, S & N Daugbjerg. 2004. Amphidinium revisited. I. Redefinition of Amphidinium (Dinophyceae) based on cladistic and molecular phylogenetic analyses. J. Phycol. 40: 351-365.

    Murray, S & D Patterson. 2002. The benthic dinoflagellate genus Amphidinium in southeastern Australian waters, including three new species. Euro. J. Phycol. 37: 279-298.

    Murray, S, Joergensen, MF, Daugbjerg, N & L Rhodes. 2004. Amphidinium revisited. II. Resolving species boundaries in the Amphidinium operculatum species complex (Dinophyceae), including the descriptions of Amphidinium trulla sp. nov. and Amphidinium gibbosum comb. nov. J. Phycol. 40: 366-382.

    Okolodkov, YB. 1998. A checklist of dinoflagellates recorded from the Russian Arctic Seas. Sarsia 83:267–92.

    Tindall, DR & SL Morton. 1998. Community dynamics and physiology of epiphytic/benthic dinoflagellates associated with ciguatera. 293-313 In: Anderson, DM, Cembella, AD & GM Hallegraeff [Eds.]. Physiological Ecology of Harmful Algal Blooms. Proceedings of the NATO-ASI, volume 41. Springer Verlag, Heidelberg.

Unless otherwise noted, all images and text by PE Hargraves
Editing and page maintenance by LH Sweat
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Page last updated: 25 September 2011


The diploid zygotic dormant stage in the sexual life cycle. Usually morphologically dissimilar from the haploid motile stage. Also called the ‘dinocyst’ or ‘hypnozygote’.

The part of a dinoflagellate cell below the cingulum. Usually refers to an ‘unarmored’ (lacking cellulose plates) cell. May also be known as the hypotheca or hyposome.

The part of a dinoflagellate cell above the cingulum; usually refers to an 'unarmored' (lacking cellulose plates) cell; may also be referred to as the hypotheca or hyposome.

A furrow encircling the cell that contains the rotary flagellum.

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