Trichodinium tenuispinum He Chengquan, 1991

Holotype: He Chengquan, 1991, pl.21, fig.16; text-fig.19
Age: Middle Eocene

Description from He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description: Cyst oval, length larger than width, with a short cylindrical apical horn (convex), size 4.5μm × 10μm; a thin antapical horn, truncated conical, about 7.5μm long. Wall thickness medium, with thin weak processes, approximately 10 around the cyst, shape and size are the same, short burr-like, straight or curved, end pointed or blunt, the relation between the distribution and tabulation is difficult to determine; The cyst wall surface between the processes is coarse granular-short wrinkled, mainly wrinkles. Lack of obvious signs of the cingulum. Archeopyle significant, precingular, P-type, formed by the movement of the third precingulr plate. The operculum is attached in situ with two burrs on it. Cyst length 60μm, width 47.5μm, process length 7.5μm, width less than 1μm.
Comparison: This species is different from Trichodinium paucispinum in possessing an antapical horn, wall surface weak burr and lack of cingulum.
Location and stratigraphy: Wuqia County Basebulak; Wulagen fm.