Baltisphaeridium hymenoferum, (Eisenack, 1938), Downie and Sarjeant, 1965

Now Peteinosphaeridium (an acritarch genus). Originally Hystrichosphaeridium, subsequently Baltisphaeridium, thirdly (and now) Peteinosphaeridium (an acritarch genus). This combination was not validly published in Eisenack, 1958 and 1959 and Downie and Sarjeant, 1963 since these authors did not fully reference the basionym.

Holotype: Eisenack, 1938, pl.3, fig.2
Age: Ordovician (based on material from an erratic)