Dinophysis acuminata

Plate 11. Dinophysis acuminata. Figs. 1-5. SEM: lateral view. Fig. 1. Cell oval and rotund; thecal surface with shallow depressions and scattered pores. Left sulcal list (LSL) extends beyond midpoint of cell. Well-developed cingular lists: anterior cingular list (ACL); posterior cingular list (PCL). C=cingulum. Fig. 2. Long and narrow cell with prominent surface areolae, each with a pore. Antapex tapered and ventrally off-center. Small posterior protrusion present (arrow). Fig. 3. Long and narrow cell. Thecal surface smooth with small scattered pores. Megacytic zone (M) void of pores. Posterior protrusions on antapex (arrow). Figs. 4-5. LM: lateral view. Fig. 4. Surface areolae and tapered antapex (from Larsen & Moestrup 1992: fig. 1d). Fig. 5. Large dorsal nucleus (N). Small, blunt projections on tapered antapex (arrow). Fig. 6. Line drawing.

D. acuminata has an oval cell shape. The posterior end of the theca can bear small teeths. The left sulcal list is well developed and of a similar depth along its length. The pore structure is usually finer than in species such as D. norvegica, but is variable.