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Gymnodinium dorsispirale
Gymnodinium dorsispirale Churchill and Sarjeant, 1962
Now Muiradinium. Originally Gymnodinium, subsequently (and now) Muiradinium.
Holotype: Churchill and Sarjeant, 1962, pl.1, fig.18, text-fig.2
Locus typicus: West Muir, Sw Australia
Stratum typicum: Holocene
Original diagnosis: Churchill and Sarjeant, 1962, p.33-34
A species of Gymnodinium having a spindle-shaped test; epitheca conical, drawn out at the apex into a nipple-like prominence, and hypotheca almost hemispherical, drawn out at the antapex into a conical prominence. Transverse furrow broad, deeply hollowed, slightly laevo-rotatory, narrowing abruptly and forming a torsion at dorsal mid-point; it is bordered on either side by raised ridges, which fade out as they approach the longitudinal furrow. Longitudinal furrow very shallow and poorly marked, broad at mid-point but tapering rapidly tov ards apex and antapex.
Original description: Churchill and Sarjeant, 1962, p.34
Shell yellowish brown, densely granular. The transverse furrow is only feebly spiral, its two ends scarcely differing in antero-posterior position. Slight striations crossing the furrow at right-angles are sometimes evident. The longitudinal furrow, always poorly marked, is in some specimens discernible only on the hypotheca.
Dimensions. Holotype: length 51 Ám, breadth 39.5 Ám. Observed range: length 45-60 Ám.
Affinities:
Churchill and Sarjeant, 1962, p.34: Gymnodinium dorsispirale differs from all described species of the genus, living or fossil, in its general form and the presence of a dorsal torsion in the transverse furrow. It is represented only in the West Muir assemblage.
Now Muiradinium. Originally Gymnodinium, subsequently (and now) Muiradinium.
Holotype: Churchill and Sarjeant, 1962, pl.1, fig.18, text-fig.2
Locus typicus: West Muir, Sw Australia
Stratum typicum: Holocene
Original diagnosis: Churchill and Sarjeant, 1962, p.33-34
A species of Gymnodinium having a spindle-shaped test; epitheca conical, drawn out at the apex into a nipple-like prominence, and hypotheca almost hemispherical, drawn out at the antapex into a conical prominence. Transverse furrow broad, deeply hollowed, slightly laevo-rotatory, narrowing abruptly and forming a torsion at dorsal mid-point; it is bordered on either side by raised ridges, which fade out as they approach the longitudinal furrow. Longitudinal furrow very shallow and poorly marked, broad at mid-point but tapering rapidly tov ards apex and antapex.
Original description: Churchill and Sarjeant, 1962, p.34
Shell yellowish brown, densely granular. The transverse furrow is only feebly spiral, its two ends scarcely differing in antero-posterior position. Slight striations crossing the furrow at right-angles are sometimes evident. The longitudinal furrow, always poorly marked, is in some specimens discernible only on the hypotheca.
Dimensions. Holotype: length 51 Ám, breadth 39.5 Ám. Observed range: length 45-60 Ám.
Affinities:
Churchill and Sarjeant, 1962, p.34: Gymnodinium dorsispirale differs from all described species of the genus, living or fossil, in its general form and the presence of a dorsal torsion in the transverse furrow. It is represented only in the West Muir assemblage.