Baltisphaeridium varispinosum, Sarjeant, 1959

Now Cleistosphaeridium. Originally Baltisphaeridium, subsequently Tenua Eisenack, 1968, thirdly Sentusidinium, fourthly Sentusidinium?, fifthly (and now) Cleistosphaeridium.

Holotype: Sarjeant, 1959, pl.13, fig.7; text-fig.6
Age: Early Callovian