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Hystrichosphaeridium geometricum*
Hystrichosphaeridium geometricum Pastiels, 1948
Name illegitimate; jr. homonym of Hystrichosphaeridium geometricum Deflandre, 1945.
Now Apectodinium geometricum. Originally Hystrichosphaeridium geometricum (name illegitimate), subsequently Baltisphaeridium geometricum, thirdly Apectodinium pastielsii (superfluous name), fourthly (and now) Apectodinium geometricum.
By transferring Hystrichosphaeridium geometricum Pastiels, 1948, to Baltisphaeridium, Downie and Sarjeant, 1965, created the valid and legitimate name Baltisphaeridium geometricum Pastiels, 1948 ex Downie and Sarjeant, 1965.
Harland, 1979, considered Hystrichosphaeridium (now Apectodinium) geometricum Pastiels, 1948, to be a synonym of Wetzeliella homomorpha var. quinquelata Williams and Downie, 1966 (now Apectodinium quinquelatum). Lentin and Williams, 1989, retained these two taxa separately. If Harland"s synonymy is followed, Apectodinium geometricum (Pastiels, 1948 ex Downie and Sarjeant, 1965) Fensome et al., 1990, would be the correct name, since it is sr. to Apectodinium quinquelatum (Williams and Downie, 1966) Costa and Downie, 1979.
Holotype: Pastiels, 1948, pl .4, fig.4
Age: Eocene
Name illegitimate; jr. homonym of Hystrichosphaeridium geometricum Deflandre, 1945.
Now Apectodinium geometricum. Originally Hystrichosphaeridium geometricum (name illegitimate), subsequently Baltisphaeridium geometricum, thirdly Apectodinium pastielsii (superfluous name), fourthly (and now) Apectodinium geometricum.
By transferring Hystrichosphaeridium geometricum Pastiels, 1948, to Baltisphaeridium, Downie and Sarjeant, 1965, created the valid and legitimate name Baltisphaeridium geometricum Pastiels, 1948 ex Downie and Sarjeant, 1965.
Harland, 1979, considered Hystrichosphaeridium (now Apectodinium) geometricum Pastiels, 1948, to be a synonym of Wetzeliella homomorpha var. quinquelata Williams and Downie, 1966 (now Apectodinium quinquelatum). Lentin and Williams, 1989, retained these two taxa separately. If Harland"s synonymy is followed, Apectodinium geometricum (Pastiels, 1948 ex Downie and Sarjeant, 1965) Fensome et al., 1990, would be the correct name, since it is sr. to Apectodinium quinquelatum (Williams and Downie, 1966) Costa and Downie, 1979.
Holotype: Pastiels, 1948, pl .4, fig.4
Age: Eocene