Tetrachacysta biconvexa subsp. laevigata

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.  Holotype: Liu Zhili et al., 1992, pl.10, fig.2.  Originally Horologinella biconvexa subsp. laevigata, subsequently (and now) Tetrachacysta biconvexa subsp. laevigata.  Age: Early Tertiary.

Parent: Tetrachacysta biconvexa