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Ovoidinium verrucosum ssp. ostium
Ovoidinium verrucosum ssp. ostium (Davey, 1970) Lentin and Williams, 1975
Originally Ovoidinium ostium, subsequently Ovoidinium verrucosum var. ostium, thirdly (and now) Ovoidinium verrucosum ssp. ostium, fourthly Ascodinium verrucosum ssp. ostium.
Helenes, 1983, retained Ascodinium verrucosum in Ascodinium Cookson and Eisenack, 1960, but failed to transfer the subspecies; this was effected by Lentin and Williams, 1985.
Lentin and Williams, 1989, retained the subspecies in Ovoidinium verrucosum.
Holotype: Davey, 1970, pl.4, fig.5
Locus typicus: Saskatchewan, Canada
Stratum typicum: Albian-Early Cenomanian
Original diagnosis: Davey, 1970, p. 353: Ovoidinium ostium
Inner body subspherical, lightly but densely granular, with moderately thick wall. Periphragm slightly granular, sometimes bearing tubercles. Apical pericoel small, with poorly. developed horn; posterior pericoel asymmetrical, possessing sub-rectangular opening on ventral surface. Cingulum and sulcus moderately well defined. Apical region generally lost in archaeopyle formation.
Dimensions: Holotype: overall length 59 Ám, length of inner body 39 Ám, width of inner body 40 Ám. Paratype: length (operculum missing) 50 Ám, length of inner body 35 Ám, width of inner body 45 Ám. Range: length (operculum missing) 37 (46 2) 63 Ám, length of inner body 28 (34.4) 45 Ám, width of inner body 37 (39.1) 54 Ám.
Original description: Davey, 1970, p. 353: Ovoidinium ostium
The inner body wall (1-1.5 Ám thick) is surrounded by an outer membrane (approximately 0.5 Ám thick), the two being in contact only in the cingular region. A characteristic sub-rectangular shaped opening is always developed on the ventral surface of the posterior pericoel membrane (text-fig. IB). The opening lies towards the posterior end of the sulcus and is typically closed by an operculum. The operculum of the apical archaeopyle is usually detached and the archaeopye margin is only sightly angular.
Originally Ovoidinium ostium, subsequently Ovoidinium verrucosum var. ostium, thirdly (and now) Ovoidinium verrucosum ssp. ostium, fourthly Ascodinium verrucosum ssp. ostium.
Helenes, 1983, retained Ascodinium verrucosum in Ascodinium Cookson and Eisenack, 1960, but failed to transfer the subspecies; this was effected by Lentin and Williams, 1985.
Lentin and Williams, 1989, retained the subspecies in Ovoidinium verrucosum.
Holotype: Davey, 1970, pl.4, fig.5
Locus typicus: Saskatchewan, Canada
Stratum typicum: Albian-Early Cenomanian
Original diagnosis: Davey, 1970, p. 353: Ovoidinium ostium
Inner body subspherical, lightly but densely granular, with moderately thick wall. Periphragm slightly granular, sometimes bearing tubercles. Apical pericoel small, with poorly. developed horn; posterior pericoel asymmetrical, possessing sub-rectangular opening on ventral surface. Cingulum and sulcus moderately well defined. Apical region generally lost in archaeopyle formation.
Dimensions: Holotype: overall length 59 Ám, length of inner body 39 Ám, width of inner body 40 Ám. Paratype: length (operculum missing) 50 Ám, length of inner body 35 Ám, width of inner body 45 Ám. Range: length (operculum missing) 37 (46 2) 63 Ám, length of inner body 28 (34.4) 45 Ám, width of inner body 37 (39.1) 54 Ám.
Original description: Davey, 1970, p. 353: Ovoidinium ostium
The inner body wall (1-1.5 Ám thick) is surrounded by an outer membrane (approximately 0.5 Ám thick), the two being in contact only in the cingular region. A characteristic sub-rectangular shaped opening is always developed on the ventral surface of the posterior pericoel membrane (text-fig. IB). The opening lies towards the posterior end of the sulcus and is typically closed by an operculum. The operculum of the apical archaeopyle is usually detached and the archaeopye margin is only sightly angular.