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Pontiadinium
From Fensome et al., 2019:
"Pontiadinium", Stover and Evitt, 1978, p.180. Taxonomic senior synonym: Komewuia, according to Chen (1982, p.36).
Type: Balteş, 1971, pl.2, fig.2, as Diconodinium inequicornutum (name not validly published).
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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.
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Emended description Baranyi et al., 2022:
Emended diagnosis. Biconical dinoflagellate cysts with single apical and antapical horns or prominent protuberances and sutural features (septa, ridges) that designate a standard S-type gonyaulacacean tabulation with neutral torsion on the dorsal surface when fully expressed. Precingular type P archeopyle formed by loss of plate 3″. Triangular precingular plate 6″ and apical plate 4′ is longer than 1′.
Emended description. Proximate, biconical, subspherical to rhomboidal organic-walled dinoflagellate cysts with distinct apical and antapical protuberances. The protuberances are conical, hollow with rounded tips and horn-like. The two protuberances can be of almost equal length or the apical protuberance can be longer. Low sutural ridges or septa formed by luxuriae distally joined by a complex tegillum together with a S-type ventral organisation indicate gonyaulacacean tabulation. The precingular 6″ plate is triangular. The tip of plate 6″ may contact apical plate 4′ or the plate may be smaller, with no contact. The apical plate 4′ is longer than 1′. When sutural septa are present, the cingulum and sulcal area are well indicated. Occasionally, the sutural septa are not well developed and the tabulation is indicated by rows of granules. The archeopyle is pentagonal, camerate precingular (type P) formed by the loss plate 3″ and with well-defined angles. The operculum may be free or adnate and folded inside the cyst. The wall is pale-transparent yellow to dark yellow in colour, with typically scabrate-granulate surface. The intratabular area is occasionally ornamented with randomly spaced low-relief granulae and papillae.
"Pontiadinium", Stover and Evitt, 1978, p.180. Taxonomic senior synonym: Komewuia, according to Chen (1982, p.36).
Type: Balteş, 1971, pl.2, fig.2, as Diconodinium inequicornutum (name not validly published).
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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.
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Emended description Baranyi et al., 2022:
Emended diagnosis. Biconical dinoflagellate cysts with single apical and antapical horns or prominent protuberances and sutural features (septa, ridges) that designate a standard S-type gonyaulacacean tabulation with neutral torsion on the dorsal surface when fully expressed. Precingular type P archeopyle formed by loss of plate 3″. Triangular precingular plate 6″ and apical plate 4′ is longer than 1′.
Emended description. Proximate, biconical, subspherical to rhomboidal organic-walled dinoflagellate cysts with distinct apical and antapical protuberances. The protuberances are conical, hollow with rounded tips and horn-like. The two protuberances can be of almost equal length or the apical protuberance can be longer. Low sutural ridges or septa formed by luxuriae distally joined by a complex tegillum together with a S-type ventral organisation indicate gonyaulacacean tabulation. The precingular 6″ plate is triangular. The tip of plate 6″ may contact apical plate 4′ or the plate may be smaller, with no contact. The apical plate 4′ is longer than 1′. When sutural septa are present, the cingulum and sulcal area are well indicated. Occasionally, the sutural septa are not well developed and the tabulation is indicated by rows of granules. The archeopyle is pentagonal, camerate precingular (type P) formed by the loss plate 3″ and with well-defined angles. The operculum may be free or adnate and folded inside the cyst. The wall is pale-transparent yellow to dark yellow in colour, with typically scabrate-granulate surface. The intratabular area is occasionally ornamented with randomly spaced low-relief granulae and papillae.