Hystrichosphaeridium diploporum Eisenack, 1951

Now Baltisphaeridium. Originally Hystrichosphaeridium, subsequently (and now) Baltisphaeridium. See also Micrhystridium (name not validly published).

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