Plate 5

Description:

Plate 5. Alexandrium ostenfeldii. Figs. 1-3. LM. Fig. 1. Ventral view. Cell large and nearly spherical. Cingulum deeply excavated. Epitheca broad and convex-conical. Hypotheca hemispherical with an obliquely flattened antapex. Fig. 2. Epitheca: apical view. Ventral pore (vp) large and distinct. First apical plate (1') forms a 90 degree angle at the point where vp and 4' plate come in contact. Apical pore complex (APC) with comma-shaped foramen. Figs. 3-4. Line drawings. Fig. 3. Ventral view: 6'' plate wider than high. Cingulum (C) slightly excavated. Fig. 4. APC and 1' plate: a. Po in direct contact with 1'; b. Po in indirect contact with 1' via thin suture. Fig. 5. LM: vegetative cell. Small equatorial nucleus (n). Fig. 6. LM: temporary cyst large and spherical, covered in mucilage. Nucleus visible (arrowhead)(Mackenzie et al. 1996).