''Gonyaulax'' is a genus of

dinoflagellate The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...

s with the type species ''Gonyaulax spinifera'' (Claparède et Lachmann) Diesing. ''Gonyaulax'' belongs to red dinoflagellates and commonly causes red tides. It secretes a poisonous toxin known as "saxitoxin" which causes paralysis in humans.

Structure

''Gonyaulax'' is a genus of dinoflagellates that are aquatic organisms with two separate

flagella A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have f ...

: one extends backward and the other wraps around the cell in a lateral groove helping to keep the organism afloat by rotational motility. The plate formula in the genus ''Gonyaulax'' Diesing was redefined as Po, 3', 2a, 6", 6c, 4-8s, 5'", 1p, 1"".

Classification

All species are marine, except for one freshwater species, ''Gonyaulax apiculata''. It previously included several species, which are now considered to belong to a separate genus, e.g.: *''Gonyaulax tamarensis'' (now: ''

Alexandrium tamarense ''Alexandrium tamarense'' is a species of dinoflagellates known to produce saxitoxin, a neurotoxin which causes the human illness clinically known as paralytic shellfish poisoning (PSP). Multiple species of phytoplankton are known to produce saxi ...

'') *''Gonyaulax grindleyi'' (now: ''Protoceratium reticulatum'') *''Gonyaulax polyedra'' (now: '' Lingulodinium polyedra'')

Adaptations

''Gonyaulax''

s have evolved a type of resting spore (or resting cyst), to enable it to survive harsh weather conditions. Resting cysts can be formed when temperature or salinity changes in the surrounding water. These cysts are round mucous covered bodies that appear reddish in color. ''Gonyaulax catenella'' has been recorded forming vegetative cysts in response to cold water.

Reproduction

''Gonyaulax'' are protists that may grow in long chains, especially when faced with turbulent water conditions. These chains allow for clustering of organisms for increased mating, and protection of weakly swimming organisms that could otherwise be washed away.

Effect on humans

Although ''Gonyaulax'' is predominantly found in seawater, it can also have a detrimental effect on humans. Filter feeding organisms (e.g. mussels, clams, etc.) can accumulate these dinoflagellates in their bodies. When humans eat these shellfish after dinoflagellate accumulation during Red Tide season, usually during the warmer months of the year, it can poison the person who eats it.

Red tide

Red tide is a discoloration of the sea water by pigmented cells like ''Gonyaulax spp.,'' some of which may produce toxins. ''Gonyaulax spinifera'' has been connected to the production of yessotoxins (YTXs), a group of structurally related polyether toxins, which can accumulate in shellfish and produce symptoms similar to those produced by paralytic shellfish poisoning (PSP) toxins.