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Ginginodinium tabulatum
Ginginodinium tabulatum Cookson and Eisenack, 1965, p.143-144
Originally (and now) Ginginodinium, subsequently Palaeoperidinium.
Lentin and Williams, 1976, transferred this species to Palaeoperidinium Deflandre, 1934. Stover and Evitt, 1978, retained it in Ginginodinium.
Holotype: Cookson and Eisenack, 1965, pl.19, figs.6-7
Locus typicus: Dilwyn Bay, Victoria, Australia
Stratum typicum: Middle Paleocene
Original description: Cookson and Eisenack, 1965, p.143
Shell thin-walled, divided almost equally by a well-marked, slightly helicoid girdle. Epitheca triangular with straight or slightly convex sides which narrow towards a short, blunt and hollow apical horn with a small terminal plug. Hypotheca trapezoidal with two short, blunt antapical horns. The longitudinal furrow is relatively broad and the curved thickening around the fagellumpore is evident in most specimens (Pl. 19, fig. 5, 6). The surface of the shell is dotted with minute spinules, some of which are so arranged as to outline the plates.
The tabulation (Fig. 3), while evident in all examples, is frequently difficult to assess with certainty since the shells are fiattened and the intercalary plates are not always clear. On the ventral surface of the epitheca in favourable specimens a long, narrow plate with slanting sides (Fig. 3, a) extends from the ends of the girdle to about three-quarters of the length of the epitheca. Adjacent to plate 1 some of the plates of the precingular circle (1[a], 2[a], ?4[a]) are recognizable. The horn is without sutures but is clearly separated from the circle of intercalary plates between which are smooth intercalary strips. No clear sutures have been observed on the ventral surface of the hypotheca.
On the dorsal surface of the epitheca three plates of the precingular circle and some intercalary plates (?2[a], 3[a], ?4[a]) are indicated; the horn is undivided. In the hypotheca three postcingular plates and the two antapical plates forming the antapical horns, separated by smooth intercalary areas, are clearly defined.
With the exception of the shape of plate 1 which is distinct from that of the rhombic plate of Peridinium the tabulation of Ginginodinium tabulatum, X[1], ?4[a], 6" or 7", 5""" or 6""", 2"""", approaches that of Peridinium.
Dimensions: Holotype c. 65 x 58 µm. Range: 58-67 µm long, c. 58-62 µm broad.
Originally (and now) Ginginodinium, subsequently Palaeoperidinium.
Lentin and Williams, 1976, transferred this species to Palaeoperidinium Deflandre, 1934. Stover and Evitt, 1978, retained it in Ginginodinium.
Holotype: Cookson and Eisenack, 1965, pl.19, figs.6-7
Locus typicus: Dilwyn Bay, Victoria, Australia
Stratum typicum: Middle Paleocene
Original description: Cookson and Eisenack, 1965, p.143
Shell thin-walled, divided almost equally by a well-marked, slightly helicoid girdle. Epitheca triangular with straight or slightly convex sides which narrow towards a short, blunt and hollow apical horn with a small terminal plug. Hypotheca trapezoidal with two short, blunt antapical horns. The longitudinal furrow is relatively broad and the curved thickening around the fagellumpore is evident in most specimens (Pl. 19, fig. 5, 6). The surface of the shell is dotted with minute spinules, some of which are so arranged as to outline the plates.
The tabulation (Fig. 3), while evident in all examples, is frequently difficult to assess with certainty since the shells are fiattened and the intercalary plates are not always clear. On the ventral surface of the epitheca in favourable specimens a long, narrow plate with slanting sides (Fig. 3, a) extends from the ends of the girdle to about three-quarters of the length of the epitheca. Adjacent to plate 1 some of the plates of the precingular circle (1[a], 2[a], ?4[a]) are recognizable. The horn is without sutures but is clearly separated from the circle of intercalary plates between which are smooth intercalary strips. No clear sutures have been observed on the ventral surface of the hypotheca.
On the dorsal surface of the epitheca three plates of the precingular circle and some intercalary plates (?2[a], 3[a], ?4[a]) are indicated; the horn is undivided. In the hypotheca three postcingular plates and the two antapical plates forming the antapical horns, separated by smooth intercalary areas, are clearly defined.
With the exception of the shape of plate 1 which is distinct from that of the rhombic plate of Peridinium the tabulation of Ginginodinium tabulatum, X[1], ?4[a], 6" or 7", 5""" or 6""", 2"""", approaches that of Peridinium.
Dimensions: Holotype c. 65 x 58 µm. Range: 58-67 µm long, c. 58-62 µm broad.