Gonyaulax

Gonyaulax is a genus of dinoflagellates with the type species Gonyaulax spinifera (Claparède et Lachmann) Diesing. Gonyaulax belongs to red dinoflagellates and commonly causes red tides. It can produce yesotoxins: for example, strains of Gonyaulax spinifera from New Zealand are yessotoxin producers.

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

Adaptations
Gonyaulax dinoflagellates can produce resting cysts that belong to the cyst-defined genus Spiniferites and other genera

Effect on humans
Although some Gonyaulax species can produce yessotoxins, which can accumulate in shellfish, no harmful effects to humans have been clearly demonstrated; however abalone mortalities have been related to blooms of Gonyaulax membranaceae.

Red tide
A 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.