Baltisphaeridium diploporum, (Eisenack, 1951), Downie and Sarjeant, 1965

Originally Hystrichosphaeridium, subsequently (and now) Baltisphaeridium; see also Micrhystridium (an acritarch genus; combination not validly published). This combination was not validly published in Downie and Sarjeant, 1963 since these authors did not fully reference the basionym.

Holotype: Eisenack, 1951, pl.2, fig.6
Age: Ordovician (based on material from an erratic)