Dinophysis tripos is a distinctive species known for its large, elongated, and asymmetrical cells. These cells have two posterior projections: a longer ventral one and a shorter dorsal one, often featuring tooth-like structures. The left sulcal list (LSL) is well-developed, widening towards the posterior and sometimes showing a reticulated pattern. The thecal plates are thick and densely covered with areolae.In terms of tabulation, the epitheca consists of four plates, and the cingulum is narrow with two distinct lists: the anterior cingular list (ACL) and the posterior cingular list (PCL), both facing forward. The ACL is supported by multiple ribs and forms a narrow, funnel-like structure that obscures the bottom of the epitheca. The sulcus comprises irregularly shaped plates and houses the flagellar pore. The LSL is notably wide, with a straight margin supported by three ribs, and a right sulcal list (RSL) is also present. The hypotheca, which makes up most of the cell, consists of four large plates. It is elongated and tapers into two posterior projections: a short dorsal one and a longer ventral one. During cell division, the dorsal projection may have a narrow list connecting two daughter cells. The ventral margin of the hypotheca is typically straight or slightly undulated, while the dorsal margin is concave below the cingulum and then convex further down toward the dorsal projection.