Baltisphaeridium tuberatum, (Downie, 1958), Downie and Sarjeant, 1965

Now Goniosphaeridium (an acritarch genus). Originally Hystrichosphaeridium, subsequently Baltisphaeridium, thirdly Acanthodiacrodium (an acritarch genus), fourthly Vulcanisphaera (an acritarch genus), fifthly (and now) Goniosphaeridium (an acritarch genus). This combination was not validly published in Downie and Sarjeant, 1963 since these authors did not fully reference the basionym. This combination is not attributable to Hu Yunxu, 1986.

Holotype: Downie, 1958, pl.17, fig.3
Age: Early Ordovician