Baltisphaeridium annulatum, (Timofeev, 1959, p.56, pl.4, fig.22)

NOW Baltisphaeridium (Acritarch). Originally Hystrichosphaeridium annulatum, subsequently (and now) Baltisphaeridium.

Holotype: Timofeev, 1959, pl.4, fig.22.
Age: Early Ordovician.