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Stephodinium australicum
Stephodinium australicum Cookson and Eisenack, 1962
Taxonomic senior synonym: Stephodinium coronatum, according to Clarke and Verdier (1967, p.67) — however, Singh (1983, p.154–155) retained Stephodinium australicum.
Holotype: Cookson and Eisenack, 1962, pl.2, fig.8
Locus typicus: Carnarvon Basin, Brickhouse Bore, at 1210 ft., W. Australia
Stratum typicum: Late Albian-Cenomanian
Original diagnosis: Cookson and Eisenack, 1962, p.491
The shell consists of an oval or ellipsoidal body and a hollow, equatorially placed wing-like outgrowth of subcircular outline when viewed in the direction of the polar axis of the body. In several examples a wide opening was evident in the slightly concave ventral edge of the wing. The body, which lies excentrically to the wing, has at least two rod-like, closely apposed apical projections, which appear to lie in a small polygonal field, and a thin, narrow membranous antapical expansion with a finely serrated edge. The wing was apparently strengthened and kept expanded by a system of fibre-like thickenings of unequal strength, which consists of (1) relatively strong fibres running parallel to the lateral edges of the wing, which give off short radial branches at intervals before turning backward, near the limits of the ventral opening, to the dorsal surface, and (2) finer fibres which, by branching or anastomosis, form a characteristic pattern on the two surfaces. A pylome, which extends from a short distance behind the apex of the body to the dorsal point of attachment of the wing, develops in the epitheca. Dimensions: Holotype: Shell 62 µm long; 45 µm broad; diameter of wing ca. 90 µm. Range: Shell 62-66 µm long; diameter of wing ca. 88-106 µm.
Remark:
Cookson and Eisenack, 1962, p.491: It is not known whether or not the slight depression in the ventral edge of the "wing" corresponds to a longitudinal furrow, nor has the significance of the opening associated with it been determined.
Taxonomic senior synonym: Stephodinium coronatum, according to Clarke and Verdier (1967, p.67) — however, Singh (1983, p.154–155) retained Stephodinium australicum.
Holotype: Cookson and Eisenack, 1962, pl.2, fig.8
Locus typicus: Carnarvon Basin, Brickhouse Bore, at 1210 ft., W. Australia
Stratum typicum: Late Albian-Cenomanian
Original diagnosis: Cookson and Eisenack, 1962, p.491
The shell consists of an oval or ellipsoidal body and a hollow, equatorially placed wing-like outgrowth of subcircular outline when viewed in the direction of the polar axis of the body. In several examples a wide opening was evident in the slightly concave ventral edge of the wing. The body, which lies excentrically to the wing, has at least two rod-like, closely apposed apical projections, which appear to lie in a small polygonal field, and a thin, narrow membranous antapical expansion with a finely serrated edge. The wing was apparently strengthened and kept expanded by a system of fibre-like thickenings of unequal strength, which consists of (1) relatively strong fibres running parallel to the lateral edges of the wing, which give off short radial branches at intervals before turning backward, near the limits of the ventral opening, to the dorsal surface, and (2) finer fibres which, by branching or anastomosis, form a characteristic pattern on the two surfaces. A pylome, which extends from a short distance behind the apex of the body to the dorsal point of attachment of the wing, develops in the epitheca. Dimensions: Holotype: Shell 62 µm long; 45 µm broad; diameter of wing ca. 90 µm. Range: Shell 62-66 µm long; diameter of wing ca. 88-106 µm.
Remark:
Cookson and Eisenack, 1962, p.491: It is not known whether or not the slight depression in the ventral edge of the "wing" corresponds to a longitudinal furrow, nor has the significance of the opening associated with it been determined.