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Dinogymnium sibiricum
Dinogymnium sibiricum (Vozzhennikova, 1967) Lentin and Williams, 1973; emend. Lentin and Vozzhennikova, 1990
Originally Gymnodinium, subsequently (and now) Dinogymnium.
Since this species was a nomen nudum in Vozzhennikova, 1963, the combination Dinogymnium sibiricum Evitt et al., 1967, was not a validly published combination.
Vozzhennikova, 1967, validly published the species name.
Holotype: Vozzhennikova, 1967, pl.3, figs.2-3; Lentin and Vozzhennikova, 1990, text-fig.8 (lost, according to Lentin and Vozzhennikova, 1990)
Lectotype: Vozzhennikova, 1967, pl.2, fig.2 (designated by Lentin and Vozzhennikova, 1990)
Locus typicus: Yuzhno-Kolpashevsk area, W Sibiria, Russia
Stratum typicum: Senonian
Translation Vozzhennikova, 1967: Lees in Sarjeant, 1971, p. 69-70
Original description: Vozzhennikova, 1967, p. 47-48: Gymnodinium sibiricum
Theca biconical. Ephitheca smaller than hypotheca, helmet-shaped, bluntly rounded at the apex. Hypotheca conical with curved sides and bluntly rounded antapex. Transverse furrow deep, annulate, its ends extending to the ventral expansion of the longitudinal furrow. The longitudinal furrow only extends a short distance onto the epitheca and hypotheca. Theca finely dotted with numerous thin longitudinal ribs which are sometimes joined together in pairs and which run from the transverse furrow towards the apical and antapical ends.
Dimensions: Holotype: length 67.6 Ám, breadth 37.8 Ám, length of epitheca 24.3 Ám, length of hypotheca 43.5 Ám, width of transverse furrow 3.0 Ám. In other specimens the length is 67.5-65.6 Ám, breadth 37.8-37.5 Ám, length of epitheca 21.6 Ám, length of hypotheca 45.9 Ám and width of transverse furrow 4.5-3.5 Ám.
Emended description: Lentin and Vozzhennikova, 1990, p. 22
Cyst shape elongate; epicyst long, conical with concave outline; hypocyst short, broadly conical; autophragm micro-porate, fine longitudinal ridges which sometimes join in pairs extent from the paracingulum to the apex and the antapex; archaeopyle formed by two arcurate sutures which results in the loss of a relatively large apical paraplate, equal to the width of the apex; paracingulum deep, dividing the cyst into two unequal portions, the epicyst being longer than the hypocyst; parasulcus indicated by a distinct break in the offset paracingulum and a shallow longitudinal depression on the hypocyst and the epicyst.
Size: Holotype: 68 Ám long, 38 Ám wide, paracingulum 3 Ám wide, range 66-68 Ám long, 37-38 Ám wide.
Affinities:
Vozzhennikova, 1967, p. 49: Gymnodinium sibiricum
This species is similar to Gymnodinium curvatum the latter however having a more attenuated and cuved hyptheca.
Originally Gymnodinium, subsequently (and now) Dinogymnium.
Since this species was a nomen nudum in Vozzhennikova, 1963, the combination Dinogymnium sibiricum Evitt et al., 1967, was not a validly published combination.
Vozzhennikova, 1967, validly published the species name.
Holotype: Vozzhennikova, 1967, pl.3, figs.2-3; Lentin and Vozzhennikova, 1990, text-fig.8 (lost, according to Lentin and Vozzhennikova, 1990)
Lectotype: Vozzhennikova, 1967, pl.2, fig.2 (designated by Lentin and Vozzhennikova, 1990)
Locus typicus: Yuzhno-Kolpashevsk area, W Sibiria, Russia
Stratum typicum: Senonian
Translation Vozzhennikova, 1967: Lees in Sarjeant, 1971, p. 69-70
Original description: Vozzhennikova, 1967, p. 47-48: Gymnodinium sibiricum
Theca biconical. Ephitheca smaller than hypotheca, helmet-shaped, bluntly rounded at the apex. Hypotheca conical with curved sides and bluntly rounded antapex. Transverse furrow deep, annulate, its ends extending to the ventral expansion of the longitudinal furrow. The longitudinal furrow only extends a short distance onto the epitheca and hypotheca. Theca finely dotted with numerous thin longitudinal ribs which are sometimes joined together in pairs and which run from the transverse furrow towards the apical and antapical ends.
Dimensions: Holotype: length 67.6 Ám, breadth 37.8 Ám, length of epitheca 24.3 Ám, length of hypotheca 43.5 Ám, width of transverse furrow 3.0 Ám. In other specimens the length is 67.5-65.6 Ám, breadth 37.8-37.5 Ám, length of epitheca 21.6 Ám, length of hypotheca 45.9 Ám and width of transverse furrow 4.5-3.5 Ám.
Emended description: Lentin and Vozzhennikova, 1990, p. 22
Cyst shape elongate; epicyst long, conical with concave outline; hypocyst short, broadly conical; autophragm micro-porate, fine longitudinal ridges which sometimes join in pairs extent from the paracingulum to the apex and the antapex; archaeopyle formed by two arcurate sutures which results in the loss of a relatively large apical paraplate, equal to the width of the apex; paracingulum deep, dividing the cyst into two unequal portions, the epicyst being longer than the hypocyst; parasulcus indicated by a distinct break in the offset paracingulum and a shallow longitudinal depression on the hypocyst and the epicyst.
Size: Holotype: 68 Ám long, 38 Ám wide, paracingulum 3 Ám wide, range 66-68 Ám long, 37-38 Ám wide.
Affinities:
Vozzhennikova, 1967, p. 49: Gymnodinium sibiricum
This species is similar to Gymnodinium curvatum the latter however having a more attenuated and cuved hyptheca.