Hystrichosphaeridium balticum Eisenack 1951

NOW Pachysphaeridium. Originally Hystrichosphaeridium, subsequently Pulvinosphaeridium (combination not validly published), thirdly Veryhachium, fourthly Goniosphaeridium, fifthly Baltisphaeridium, sixthly Estiastra, seventhly (and now) Pachysphaeridium.

Holotype: Eisenack 1951, pl.3, fig.10
Age: Early Ordovician