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.
The plate formula in the genus Gonyaulax Diesing was redefined as Po, 3’, 2a, 6”, 6c, 4-8s, 5’”, 1p, 1””
Gonyaulax spinifera has been related to production of Yessotoxins (YTXs), a group of structurally related polyether toxins, which can accumulate in shellfish and can produce symptoms similar to those produced by Paralytic Shellfish Poisoning (PSP) toxins.
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 polyedrum)