Baltisphaeridium meson, [Eisenack, 1955 nom. subst. pro Hystrichosphaeridium intermedium Eisenack, 1954 non Hystrichosphaeridium intermedium (O. Wetzel, 1933) Deflandre, 1937], Downie and Sarjeant, 1965

Now Visbysphaera meson (an acritarch species). Originally Hystrichosphaeridium intermedium (name illegitimate), subsequently Hystrichosphaeridium meson, thirdly Baltisphaeridium meson, fourthly (and now) Visbysphaera meson (an acritarch species), fifthly Multiplicisphaeridium meson (an acritarch species).
Tax. sr. synonym of the acritarch species Multiplicisphaeridium (al. Baltisphaeridium) micropilare Cramer, 1970 ex Eisenack et al., 1973, according to Ye Xiarong, 1984. This combination was not validly published in Downie, 1959 and Downie and Sarjeant, 1963, since these authors did not fully reference the basionym.

Holotype: Eisenack, 1954, pl.1, fig.3
Age: Silurian (Late Llandovery-Late Ludlow)