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Impletosphaeridium ligospinosum
From Fensome et al., 2019:
Impletosphaeridium ligospinosum (de Coninck, 1969, p.50, pl.15, figs.9–19) Islam, 1983a, p.240. Holotype: de Coninck, 1969, pl.15, fig.19; Fauconnier and Masure, 2004, pl.49, fig.7. Originally Baltisphaeridium (Appendix A), subsequently (and now) Impletosphaeridium. Age: Early Eocene.
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Original description (De Coninck, 1969)
Diagnosis: The organism consists of a relatively small, globose or oval shell bearing very fine, solid, straight processes with an asymmetrical bifurcation at their distal end: one of the two small forks is less developed than the other and its reduction is often almost complete. Thus, the tips of the processes resemble a hoe or a pickaxe (Latin: ligo). A very thin membrane has sometimes detached from the shell surface and is raised by the fine processes. The length of the processes is about half the shell dimensions.
Shell dimensions: 20 µm to 25 µm.
Process dimensions: about 8 µm.
Total wingspan: between 30 µm and 40 µm.
Note: The species at first sight resembles B. polytrichum (Valensi, 1947), C. R. Ac. Sc., 225, p. 818, fig. 4, and could be confused with it, because the specific characters are difficult to see, but the tips of the processes in Valensi's species never show this hoe shape.
Impletosphaeridium ligospinosum (de Coninck, 1969, p.50, pl.15, figs.9–19) Islam, 1983a, p.240. Holotype: de Coninck, 1969, pl.15, fig.19; Fauconnier and Masure, 2004, pl.49, fig.7. Originally Baltisphaeridium (Appendix A), subsequently (and now) Impletosphaeridium. Age: Early Eocene.
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Original description (De Coninck, 1969)
Diagnosis: The organism consists of a relatively small, globose or oval shell bearing very fine, solid, straight processes with an asymmetrical bifurcation at their distal end: one of the two small forks is less developed than the other and its reduction is often almost complete. Thus, the tips of the processes resemble a hoe or a pickaxe (Latin: ligo). A very thin membrane has sometimes detached from the shell surface and is raised by the fine processes. The length of the processes is about half the shell dimensions.
Shell dimensions: 20 µm to 25 µm.
Process dimensions: about 8 µm.
Total wingspan: between 30 µm and 40 µm.
Note: The species at first sight resembles B. polytrichum (Valensi, 1947), C. R. Ac. Sc., 225, p. 818, fig. 4, and could be confused with it, because the specific characters are difficult to see, but the tips of the processes in Valensi's species never show this hoe shape.