The valves of T. eccentrica are flat and feature a rounded mantle. The connecting thread is approximately twice the length of the cell’s diameter. When viewed from the valve side, the areolae are arranged in tangential rows, forming a somewhat clustered pattern. There is a single central process positioned near a central areola and surrounded by seven areolae. The strutted processes are distributed across the valve surface and are found both within two marginal rings and as a ring of pointed spines located inside the outer marginal rings of strutted processes. Additionally, one labiate process is observed.