Tetrachacysta biconvexa subsp. laevigata (Zheng Yuefang and Liu Xuexian in Liu Zhili et al., 1992, p.69–70, pl.10, figs.1–2) He Chengquan et al., 2009, p.374.

Originally Horologinella biconvexa subsp. laevigata, subsequently (and now) Tetrachacysta biconvexa subsp. laevigata.

Holotype: Liu Zhili et al., 1992, pl.10, fig.2.
Age: Early Tertiary.