Description of Thoracosphaerales
provided by BioPedia
Dinoflagellates, free living with calcareous-walled coccoid cell the most common form; weakly calcified cells may divide, heavily calcified cells release a cell with two nuclei which then divides; uncalcified ellipsoidal nonmotile cell also produced and these divide to produce two nonmotile daughter cells (aplanospores); division products will re-calcify during which time flagella are lost.