Hystrichosphaeridium piriferum

"piriferum" Eisenack, 1954a, p.206–207, pl.1, figs.1a–b; text-fig.1.  Holotype: Eisenack, 1954a, pl.1, figs.1a–b.  NOW Visbysphaera (Appendix A).  Originally Hystrichosphaeridium, subsequently Baltisphaeridium (Appendix A), thirdly Multiplicisphaeridium (Appendix A), fourthly (and now) Visbysphaera (Appendix A).  Taxonomic junior synonyms: Baltisphaeridium hermosum Cramer and Diez, 1968 (name not validly published), an acritarch species, according to Cramer (1970, p.148); Baltisphaeridium (now Visbysphaera) dilatispinosum Downie, 1963, an acritarch species, according to Eisenack (1965c, p.263) — however, Fensome et al. (1990, p.530) retained Baltisphaeridium (now Visbysphaera) dilatispinosum.  Age: Silurian (late Llandovery).

Parent: Hystrichosphaeridium