Hystrichosphaeridium spiralisetum De Wit, 1943

Now Cleistosphaeridium. Originally Hystrichosphaeridium, subsequently Baltisphaeridium, thirdly (and now) Cleistosphaeridium.
Holotype: De Wit, 1943, text-figs.2,11 (the type material was not preserved)
Age: Late Cretaceous