Baltisphaeridium erraticum, (Eisenack, 1954), Downie and Sarjeant, 1965

Now Visbysphaera (an acritarch genus). Originally Hystrichosphaeridium, subsequently Baltisphaeridium, thirdly (and now) Visbysphaera (an acritarch genus), fourthly Multiplicisphaeridium (an acritarch genus). This combination was not validly published in Downie and Sarjeant, 1963 and Cramer, 1964 since these authors did not fully reference the basionym.

Holotype: Eisenack, 1954, pl.1, fig.6
Age: Silurian (Late Ludlow)