Baltisphaeridium seminudum, (W. Wetzel, 1952), Downie and Sarjeant, 1965

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

Holotype: W. Wetzel, 1952, text-fig.26
Age: Early Paleocene (Danian)