From Williams et al., 2017:

[Pontiadinium, Stover and Evitt, 1978, p. 180

Type species: originally as as Diconodinium inequicornutum (name not validly published), Balteş, 1971 (pl.2, fig.2)] ; Pontadinium inequicornutum

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Original description: [Stover and Evitt, 1978]:

Synopsis:
Cysts biconical with single apical and antapical horns; autophragm ornamented with features of low relief; paratabulation indicated by precingular, Type P, archeopyle only.

Description:
Shape: Cyst biconical with prominent apical horn and a generally shorter antapical horn.
Wall relationships: Autophragm only.
Wall features: Generally without parasutural features; autophragm smooth, granular, or punctoreticulate.
Paratabulation: Generally indicated by archeopyle only.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Not indicated, or shown by parallel, low, transverse equatorial ridges.
Parasulcus: Not indicated.
Size: Small to intermediate.

Affinities:
Pontiadinium differs from Fusiformacysta in having a simple Type P archeopyle rather than a compound Type 2P to ?5P archeopyle. It differs from Omatia in lacking parasutural features (except occasionally for specimens showing a paracingulum) and in being less elongate. Pontiadinium is similar to Kalyptea and Diconodinium, which have intercalary archeopyles rather than a precingular archeopyle.