The life history of Alexandrium pseudogonyaulax (Gonyaulacales, Dinophyceae)

Alexandrium pseudogonyaulax (Biecheler) Horiguchi ex Yuki et Fukuyo (Gonyaulacales, Dinophyceae) is a phototrophic marine dinoflagellate that produces an unusual paratabulate resting cyst. Studies of vegetative and sexual reproduction were conducted on a clonal culture established from germination of a resting cyst from Fusaro Lagoon. Italy. Vegetative division in A. pseudogonyaulax takes place inside a vegetative cyst, from which two, or at times four, daughter cells originate. The daughter cells completely resynthesize new cell walls. Cyst formation takes place after sexual reproduction. A large biflagellate zygote is formed after a conjugation process in which one of the two gametes is engulfed by the other.