From Fensome et al., 2019:
Sentusidinium shangsicum (He Chengquan, 1984b) comb. nov. Chytroeisphaeridia shangsica He Chengquan, 1984b p.162, pl.8, figs.16–19. Holotype: He Chengquan, 1984b, pl.8, fig.16. Originally Chytroeisphaeridia, subsequently Escharisphaeridia, thirdly (and now) Sentusidinium. Here we propose the combination Sentusidinium shangsicum as the genus Escharispheridia is now considered a taxonomic junior synonym of Sentusidinium. Age: Tertiary.

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Original description: [He Chengquan, 1984b] (translated from Chinese with Google):

Chytroeisphaeridia shangsica (sp. nov.)
(Plate VIII, Figures 16-19)

Description: The shell is spherical, with a nearly circular outline. It lacks a roof, caudal bulge, girdle, or plate. The shell wall is thin and single-layered; the surface is smooth. The palate is polygonal, and the operculum may be only partially preserved and is usually connected. It may be wrinkled or have a nucleus.

Shell diameter 50-55 μm; holotype diameter 52.5 μm.

This species is different from other species in this genus in that its ancient mouth is larger and its outline is nearly 5-6 sided.

Origin: Shangsi, Guangxi; the second section of the Yongning Group.