Tetrachacysta biconvexa (Jiabo, 1978, p.95, pl.29, figs.20–21) He Chengquan et al., 2009, p.374.

Originally Horologinella, subsequently (and now) Tetrachacysta.

Holotype: Jiabo, 1978, pl.29, fig.21.
Age: Early Tertiary.