Diagnosis. -Moderate to large compared with T. paraboloides, T. cysticus or T. minutus, 0.5-4.0 mm diameter, (x = 1.61,
SD = 0.99, N = 22); few (maximum 7) pits per calyx; shallow pits (depth/diameter ratio 1:6); typically with flattened, slightly irregular floors. Pits exhibit a faint and often incomplete ring (circular groove), concentric with outer borders; generally 0.2-0.5 mm inward from main border, but may occur outside outer border; pits frequently intersect.