Hystrichosphaeridium microspinosum Eisenack, 1954

Now Visbysphaera. Originally Hystrichosphaeridium, subsequently Baltisphaeridium, thirdly Lophosphaeridium, fourthly (and now) Visbysphaera. See also Buedingiisphaeridium (combination not validly published).
Holotype: Eisenack, 1954, pl.1,fig.8
Age: Silurian (Late Llandovery)