SPECIES DESCRIPTION:
Dinophysis caudata is a unicellular thecate dinoflagellate with a laterally compressed cell, a large hypotheca and a comparatively small epitheca. Species of Dinophysis normally have 19 plates. The majority of the cell size consists of the four plates of the hypotheca, and there are also six in the epitheca, four in the cingulum and five in the sulcus. Except for the hypotheca, most plates are not visible. In D. caudata, the cingulum and sulcus have transparent extensions on either side called lists (see general morphology illustration of Dinophysiales on the Dinoflagellates page), smaller on the cingulum and well developed on the sulcus. Sulcal lists have ribs, normally three, and the left sulcal list is larger than the other. Within the genus, these features have identification significance. The anterior cingular list is funnel-shaped and conceals the epitheca in the broad lateral view of the cell.