158,849 species and infraspecific names are in the database, 22,385 images, 61,534 bibliographic items, 456,806 distributional records.

Gyrodinium Kofoid & Swezy, 1921, nom. cons.

Empire Eukaryota
Kingdom Chromista
Subkingdom Harosa (supergroup SAR)
Infrakingdom Halvaria
Phylum Miozoa
Subphylum Myzozoa
Infraphylum Dinozoa
Superclass Dinoflagellata
Class Dinophyceae
Order Gymnodiniales
Family Gyrodiniaceae

Holotype species: Gyrodinium spirale (Bergh) Kofoid & Swezy

Original publication and holotype designation: Kofoid, C.A. & Swezy, O. (1921). The free-living unarmored Dinoflagellata. Memoirs of the University of California 5: i-viii, 1-562.
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Taxonomic status: currently recognized as a distinct genus.

Most recent taxonomic treatment adopted: Moestrup, Ø. & Calado, A.J. (2018). Süßwasserflora von Mitteleuropa. Freshwater Flora of Central Europe, Volume 6: Dinophyceae. pp. [i]-xii, [1]-560, 421 figs. Berlin: Springer Spektrum.

Description: Small-to-large (<5-<200 µm) unarmored unicellular free-living, predominantly motile flagellates, sometimes enclosed in temporary cysts. Cells globular to fusiform, often dorsiventrally, rarely laterally compressed, with well-developed cingulum and sulcus, transverse and longitudinal flagella. Cingulum displaced at least 1/5 of total body length (for less cingulum displacement, see Gymnodinium). Cingulum with one turn to 1.5 turns if the cell shows torsion (for greater torsion, see Cochlodinium). Sulcus restricted to hypocone or extending to the epicone. Amphiesma delicate to rigid, smooth or with conspicuous striae on hypocone or extending to epicone. Number on epicone may be larger than on hypocone. Typical dinokaryon in some species enclosed by a perinuclear sheet, visible by light microscopy. Chloroplasts absent or present, some species with chloroplast pigments typical for prymnesiophytes, lacking the dinoflagellate pigment peridinin; pigments of other species with unusual chloroplast color not analyzed. Some species with stigma. Cytoplasm either colorless or of various colors. Nutrition phototrophic, mixotrophic, phagotrophic, or by absorption of dissolved organic material. Some species produce temporary cysts by secreting hyaline sheets, and may be confused with coccoid dinophytes. Vegetative reproduction by binary fission, sexual reproduction, including the production of hypnozygotes acting as resting cysts, known for some species. Cosmopolitan, marine, brackish and freshwater; some species inhabit snow and ice. Several species form large blooms. Gyrodinium aureolum Hulburt or a similar species, assigned also to Gymnodinium cf. nagasakiense Takayama and Adachi, produces ichthyotoxins of economic importance. Emended by G. Hansen & Moestrup (2000: 312).

Information contributed by: M. Elbrächter. The most recent alteration to this page was made on 18 Oct 2018 by M.D. Guiry.

Characters considered diagnostic of Gyrodinium: Girdle characteristically descending in a left spiral displaced more than 0.2 of the total body length.Sulcus longitudinal, or with torsion of less than half a transdiameter in the intercingular region, extending from girdle or epicone to hypocone or antapex. The nucleus is usually situated near the centre. Pusules may be present. Chromatophores rarely present. Surface smooth or with longitudinal striations. Cells shape variable but frequently ovoid or fusiform with girdle centrally positioned although epicone and hypocone can be subequal. Cells vary in lenght from 11 um to 200um. They occur in marine, brackish or freshwater and are pelagic, neriticor littoral (living in sand). Two sorts of cysts have been described a thin-walled capsule in which the individual cell retains its shape before fission and a sphaerical cyst where the individual cell rounds off, loses its flagella and is resistant (Silva, 1959).

Comments: Problems with identification This is clearly an artificial genus for when Kofoid & Swezy (1921) set it apart from the genus Gymnodinium the main criterion was that the girdle is displaced more than one fifth the length of the body. Consequently, identification of members of this genus can be problematical since the shape frequently changes under the microscope and with fixation. Shape can also be affected by changes in salinity. It is also difficult to separate this genus from Gymnodinium. Bursa (1962) has shown that Gyrodinium californicum Bursa divides to give two daughter cells one resembling a Gyrodinium , the other a Gymnodinium. Kimball & Wood (1962) working with an organism identified as Gymnodinium mirabile Penard noted different forms resembling Gymnodinium fissum (Levander) Kof. & Swezt, Gyrodinium nelsoni Martin in culture. Gyrodinium aureolum was found to become Gymnodinium like on preservation and when left in continuous dark (Braarud & Heimdal, 1970). According to Daugberg et al. (2000: 312), Gymnodinium aureum Kofoid & Swezy belongs to Gyrodinium as emended by them.

Numbers of names and species: There are 136 species names in the database at present, as well as 1 infraspecific names. Of the species names, 105 have been flagged as accepted taxonomically on the basis of the listed literature under the species name. In some instances, opinions on taxonomic validity differ from author to author and users are encouraged to form their own opinion. AlgaeBase is a work in progress and should not be regarded as a definitive source only as a guide to the literature..

Names: ('C' indicates a name that is accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):

Click here to also show infraspecific names in the list below.

Dodge, J.D. (1982). Marine dinoflagellates of the British Isles. pp. 1-303, 35 figs, pls I-VIII. London: Her Majesty's Stationery Office.

Carty, S. (2003). Dinoflagellates. In: Freshwater Algae of North America, Ecology and Classification. (Wehr, J.D. & Sheath, R.G. Eds), pp. 685-714. San Diego: Academic Press.

Daugbjerg, N., Hansen, G., Larsen, J. & Moestrup, Ø. (2000). Phylogeny of some of the major genera of dinoflagellates based on ultrastructure and partial LSU rDNA sequence data, including the erection of three new genera of unarmoured dinoflagellates. Phycologia 39: 302-317.

Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.

Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in CD format. These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above. The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.

Descriptions of chrysophyte genera were subsequently published in J. Kristiansen & H.R. Preisig (eds.). 2001. Encyclopedia of Chrysophyte Genera. Bibliotheca Phycologica 110: 1-260.

Created: 06 September 2004 by M.D. Guiry

Verified by: 27 September 2018 by M.D. Guiry

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M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 04 August 2020.

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