Description of Peridiniales
Tabulation exhibits, or is derived from, a pattern in which there is symmetry about the first apical plate (the left lateral triple junction(s) essentially level with the right lateral triple junction(s) and there are 2 antapical plates placed symmetrically about the midventral / middorsal plane. The apical pore complex commonly includes a small canal plate ventrally which may be elongate towards the first apical plate. The first apical homologue commonly contacts this small plate but not the remainder of the apical pore complex. There are 6-9 climactal plates: 4 apical; 2-4 dorsal anterior intercalary plates. The majority of taxa possess 7 precingular and 5 postcingular plates. The sulcus typically has 4 large plates; additional small platelets may be associated with the flagellar pore. A transitional cingular-sucal plate (t) is usually found at the proximal end of the cingulum to the left of the anterior sucal plate.