Gonyaulax Diesing, 1866

Holotype species: Gonyaulax spinifera (Claparède & Lachmann) Diesing

Original publication and holotype designation: Diesing, K.M. (1866). Revision der Prothelminthen. Abtheilung: Mastigophoren. Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften. Mathematisch-Naturwissenschaftliche Classe. Abt. 1, Mineralogie, Botanik, Zoologie, Anatomie, Geologie und Paläontologie 52: 287-401.

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Description: Small-to-large (25-175 µm) biflagellated, heterodynamic flagellates with cell wall of cellulosic plates. Plate formula of the type species : Po, 3', 2a, 6", 4-8s, 5"', 1p, 1"" (after Dodge 1989). Other authors interpret the plate formula differently, in addition some of the species now included into Gonyaulax really have a different plate formula. The following description applies to the type species and similar taxa. The cell shows a marked asymmetry due to torsion. The cingulum starts median ventrally, turning to the left in a descending spiral, making more than one loop. Therefore the sulcus, starting at the beginning of the cingulum mid-ventrally is not straight but twisted posteriorly. Few to several spines are on the hypotheca plates. One multilobed chloroplast merges centrally in an extensive central pyrenoid complex without starch sheet. The large, U-shaped nucleus is located in the dorsal posterior end of the cell. Trichocysts are formed in golgi-derived vesicles. There are two large pusule-sacs. The flagellar apparatus is complex and resembles that of other species of the gonyaulacoid lineage. At least some species now assigned to Gonyaulax are bioluminescent including the type species. Many species of different morphology also are included into Gonyaulax, as G. polyedra (assigned by some authors to Lingulodinium) which is a model organism for research on circadian rhythms, photoperiodisms, and bioluminescence. In addition, the vertebrate pineal hormone melatonin has been discovered in unicellular algae for the first time in G. polyedra. Some species have been shown to be mixotrophic with ingesting prey organisms. Vegetative reproduction by binary fission, the theca of the mother cell is split along a characteristic fission line and shared by the two daughter cells. Cysts of various morphology and assigned to different cyst-genera have been shown to produce vegetative cells identified with the type species of Gonyaulax, G. spinifera. These are: Spiniferites Mantell 1850; ; Nematosphaeropsis Deflandre and Cookson 1955; Tectactodinium Wall 1967; Ataxiodinium Reid 1974; Bitectatodinium Reid 1974; Impaginidium Stover et Evitt 1978.

Information contributed by: M. Elbrächter. The most recent alteration to this page was made on 2022-06-17 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

Gender: This genus name is currently treated as feminine.

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.

Comments: Habitat: Marine plankton of polar to tropical waters, world-wide; at least one species in freshwater lakes of Europe. The taxonomy of this genus is under discussion. After separation of the species now assigned to the genera Alexandrium Halim, Amylax Meunier and Protoceratium Bergh there are species with morphology and plate pattern different from that of the type species. Some authors have placed Gonyaulax polyedra into the genus Lingulodinium Wall, the type of which is a fossil. According to Zonneveld and Dale (1994), it is premature to subdivide the genus further at the present state of knowledge and this line is followed here. The insufficiently described type species of the monospecific genus Melanodinium Schiller was redescribed and transferred to Gonyaulax.

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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.

Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=44645

Citing AlgaeBase
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M.D. Guiry in Guiry, M.D. & Guiry, G.M. 17 June 2022. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 04 December 2022

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