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Spinidinium echinoideum ssp. rhombicum
Spinidinium echinoideum ssp. rhombicum (Cookson and Eisenack, 1974) Lentin and Williams, 1976
Originally Deflandrea rhombica, subsequently (and now) Spinidinium echinoideum ssp. rhombicum, thirdly Spinidinium rhombicum. Lentin and Williams, 1976 lowered this taxon to the subspecies level as Spinidinium echinoideum ssp. rhombicum. Stover and Evitt, 1978 retained the taxon at the species rank as Spinidinium rhombicum (Cookson and Eisenack, 1974) Stover and Evitt, 1978; however, Lentin and Williams, 1981 followed Lentin and Williams, 1976.
Holotype: Cookson and Eisenack, 1974, pl.20, fig.7
Locus typicus: Perth Basin, Australia
Stratum typicum: Albian-Cenomanian
Original diagnosis: Cookson and Eisenack, 1974, p. 49: Deflandrea rhombica
Overall shape rhombic. Periphragm flattened, epicyst triangular with slightly concave to convex flanks. Weakly developed, blunt apical horn. Hypocyst triangular with pointed antapical horn. Hypocyst trapezoidal when second, weakly developed antapical horn present. Usually just one, pointed to thorn-like antapical horn present, which may be displaced towards the girdle. Girdle relatively wide but indistinct. Periphragm with short, pointed spines, strongest developed on girdle folds. Apex with few (2-4) diverging folds. Endophragm circular and clearly distinguished from the periphragm. Archaeopyle usually present, trapezoidal to rounded triangular.
Dimensions: Holotype c. 72-50 µm, range - length 57-90 µm, breadth 38-76 µm; length/breadth ratio 1,4 - 1,6:1.
Originally Deflandrea rhombica, subsequently (and now) Spinidinium echinoideum ssp. rhombicum, thirdly Spinidinium rhombicum. Lentin and Williams, 1976 lowered this taxon to the subspecies level as Spinidinium echinoideum ssp. rhombicum. Stover and Evitt, 1978 retained the taxon at the species rank as Spinidinium rhombicum (Cookson and Eisenack, 1974) Stover and Evitt, 1978; however, Lentin and Williams, 1981 followed Lentin and Williams, 1976.
Holotype: Cookson and Eisenack, 1974, pl.20, fig.7
Locus typicus: Perth Basin, Australia
Stratum typicum: Albian-Cenomanian
Original diagnosis: Cookson and Eisenack, 1974, p. 49: Deflandrea rhombica
Overall shape rhombic. Periphragm flattened, epicyst triangular with slightly concave to convex flanks. Weakly developed, blunt apical horn. Hypocyst triangular with pointed antapical horn. Hypocyst trapezoidal when second, weakly developed antapical horn present. Usually just one, pointed to thorn-like antapical horn present, which may be displaced towards the girdle. Girdle relatively wide but indistinct. Periphragm with short, pointed spines, strongest developed on girdle folds. Apex with few (2-4) diverging folds. Endophragm circular and clearly distinguished from the periphragm. Archaeopyle usually present, trapezoidal to rounded triangular.
Dimensions: Holotype c. 72-50 µm, range - length 57-90 µm, breadth 38-76 µm; length/breadth ratio 1,4 - 1,6:1.