From Fensome et al., 2019:
Tetrachacysta biconvexa (Jiabo, 1978, p.95, pl.29, figs.20–21) He Chengquan et al., 2009, p.374.
Holotype: Jiabo, 1978, pl.29, fig.21.
Originally Horologinella, subsequently (and now) Tetrachacysta.
Age: early Tertiary.

---------------------------------------------------------------------------------------------------