portrait

Description:

Prorocentrum rhathymum cells are asymmetrical oval in valve view, with the left side of the right valve slightly longer at the apical end. Valve length 29 - 40 microns, valve width 18 - 27microns, length to width ratio 1.4 -1.6. The apical area is a small indentation, covered by many small pores. A spine (approximately 2 microns long) is present to the right of the apical area on the right valve. Cell surface smooth, with large (0.5 microns ) pores, which are arranged in rows radiating from the periphery of the valve. Very small pores (approximately 0.1 microns ) also present. Extrusomes (3 - 5 microns ) are present in the anterior part of the valve, pointing in the direction of the apical area. Nucleus 10 microns diameter, in the posterior part of the valve. Plastid yellow-brown, diffuse.