From Williams et al., 2017:

[Xuidinium, Mao Shao-zhi and Norris, 1988, p. 53–54

Type species: Xuidinium laevigatum, Mao Shao-zhi and Norris, 1988 (pl.16, fig.10)]

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Original description: [Mao Shao-zhi and Norris, 1988]:

Diagnosis:
Cyst proximate; ambitus rounded biconical with an apical and an antapical prominence, right antapical part either without horn or slightly bulging. Autophragm smooth or uniformly ornamented with features of low relief.
Tabulation indicated by archeopyle only or by archeopyle and cingulum together.
Archeopyle intercalary, type I, hexa 2a.