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Cleistosphaeridium heteracanthum
From Fensome et al., 2019:
Cleistosphaeridium heteracanthum (Deflandre and Cookson, 1955, p.276, pl.2, figs.5–6; text-figs.40–41) Davey et al., 1966, p.168. Emendation: Radmacher et al., 2014, p.33,36, as Heterosphaeridium heteracanthum. Holotype: Deflandre and Cookson, 1955, pl.2, fig.5; Fauconnier and Masure, 2004, pl.35, figs.7–8. NOW Heterosphaeridium. Originally Hystrichosphaeridium, subsequently Baltisphaeridium (Appendix A), thirdly Cleistosphaeridium, fourthly (and now) Heterosphaeridium, fifthly Heterosphaeridium? Age: Late Cretaceous–Early Eocene.
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Original description as Hystrichosphaeridium heteracanthum: [Deflandre and Cookson, 1955, p. 276]:
Description:
Shell large, approximately circular in outline, with numerous appandages of variable size, shape and form. Appandages solid, usually elongated, frequently filiform, sometimes as broad as long, the apices either pointed, averted, or irregularly branched.
Surface of shell punctate.
Dimensions:
Shell 56-107 µm, appandages 5-36 µm long (majority between 13 and 23 µm).
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Emended description: [Radmacher et al., 2014, p.33,36, as Heterosphaeridium heteracanthum]:
Emended diagnosis (based on original description and photograph of Deflandre and Cookson, 1955, pl. 2, figs. 5, 6): Large, gonyaulacacean, circular in outline, chorate to proximo-chorate cyst with an apical archaeopyle. Numerous, non-tabular processes are characterised by variable shape, length and width. All processes are solid, usually elongated and their endings differ significantly. They may be pointed, everted or irregularly branched, never “scythe-like” or distally connected. Wall structure is punctate.
Comparison to Heterosphaeridium bellii: Heterosphaeridium heteracanthum differs significantly from H. bellii sp. nov. by having solid processes of variable length and width, often strongly branched and furcated at the ends and never “scythe-shaped” terminations. The processes of H. bellii sp. nov. are rather constant in length and possess different, “scythe-shaped” types of terminations. They are solid and hollow on one specimen. Some of the processes may be solid in the middle and hollow at the ends. The endings are never branched as in H. heteracanthum. Additionally, crests observed in H. heteracanthum are much taller and more commonly observed than in H. bellii sp. nov.
Cleistosphaeridium heteracanthum (Deflandre and Cookson, 1955, p.276, pl.2, figs.5–6; text-figs.40–41) Davey et al., 1966, p.168. Emendation: Radmacher et al., 2014, p.33,36, as Heterosphaeridium heteracanthum. Holotype: Deflandre and Cookson, 1955, pl.2, fig.5; Fauconnier and Masure, 2004, pl.35, figs.7–8. NOW Heterosphaeridium. Originally Hystrichosphaeridium, subsequently Baltisphaeridium (Appendix A), thirdly Cleistosphaeridium, fourthly (and now) Heterosphaeridium, fifthly Heterosphaeridium? Age: Late Cretaceous–Early Eocene.
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Original description as Hystrichosphaeridium heteracanthum: [Deflandre and Cookson, 1955, p. 276]:
Description:
Shell large, approximately circular in outline, with numerous appandages of variable size, shape and form. Appandages solid, usually elongated, frequently filiform, sometimes as broad as long, the apices either pointed, averted, or irregularly branched.
Surface of shell punctate.
Dimensions:
Shell 56-107 µm, appandages 5-36 µm long (majority between 13 and 23 µm).
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Emended description: [Radmacher et al., 2014, p.33,36, as Heterosphaeridium heteracanthum]:
Emended diagnosis (based on original description and photograph of Deflandre and Cookson, 1955, pl. 2, figs. 5, 6): Large, gonyaulacacean, circular in outline, chorate to proximo-chorate cyst with an apical archaeopyle. Numerous, non-tabular processes are characterised by variable shape, length and width. All processes are solid, usually elongated and their endings differ significantly. They may be pointed, everted or irregularly branched, never “scythe-like” or distally connected. Wall structure is punctate.
Comparison to Heterosphaeridium bellii: Heterosphaeridium heteracanthum differs significantly from H. bellii sp. nov. by having solid processes of variable length and width, often strongly branched and furcated at the ends and never “scythe-shaped” terminations. The processes of H. bellii sp. nov. are rather constant in length and possess different, “scythe-shaped” types of terminations. They are solid and hollow on one specimen. Some of the processes may be solid in the middle and hollow at the ends. The endings are never branched as in H. heteracanthum. Additionally, crests observed in H. heteracanthum are much taller and more commonly observed than in H. bellii sp. nov.