Dinophysis caudata is a distinct species characterized by its large, elongated, and irregularly oval cells with an extended projection on the lower side. This projection often resembles tooth-like structures at its rear. The left side of the cell features a lengthy sulcal list (LSL) that extends to nearly half the cell’s length, with the widest point usually at the LSL’s base. The sturdy protective plates are notable for their pore-covered surface. Cell size falls within the range of 70-110 µm in length and 37-50 µm in width at the LSL’s base.
The front part of the cell comprises four plates, with a narrow cingulum housing anterior and posterior cingular lists (ACL and PCL). The sulcus contains irregularly shaped plates and the flagellar pore. The LSL, supported by three ribs, and a right sulcal list (RSL) often exhibit a network-like pattern. The majority of the cell, the hypotheca, consists of four substantial plates, is elongated, narrows at the lower end, and occasionally bears small knob-like structures.