Abantosphaeridium
Abratopdinium
Acanthaulax
Acanthogonyaulax
Achilleodinium
Achomosphaera
Actiniscus
Actinotheca
Adnatosphaeridium
Agerasphaera
Aiora
Aiora
Aireiana
Alaskadinium
Alasphaera
Albertia
Aldorfia
Algidasphaeridium
Alisocysta
Alisogymnium
Alterbia
Alterbidinium
Ambonosphaera
Amiculosphaera
Amphidiadema
Amphigymnium
Amphora
Amphorosphaeridium
Amphorula
Andalusiella
Andreedinium
Angustidinium
Apectodinium
Apiculadinium
Aprobolocysta
Aptea
Apteodinium
Aquadulcum
Arachnodinium
Araneosphaera
Archeotectatum
Areoligera
Areosphaeridium
Arkellea
Arkellidinium
Arpylorus
Arvalidinium
Ascodinium
Astrocysta
Ataxiodinium
Athigmatocysta
Atlantodinium
Atopodinium
Australiella
Australisphaera
Avellodinium