Baltisphaeridium meson Appendix A

"meson" (Eisenack, 1955, p.179) Downie and Sarjeant, 1965, p.92.  Holotype: Eisenack, 1954a, pl.1, fig.3.  NOW Visbysphaera mesa (Appendix A).  Originally Hystrichosphaeridium intermedium (name illegitimate), subsequently Hystrichosphaeridium meson, thirdly Baltisphaeridium meson, fourthly (and now) Visbysphaera mesa (Appendix A), fifthly Multiplicisphaeridium meson (Appendix A).  Hystrichosphaeridium meson is the substitute name for Hystrichosphaeridium intermedium Eisenack, 1954a, p.208, pl.1, figs.3,9; text-figs.3-4 (an illegitimate name).  Taxonomic junior synonym: Baltisphaeridium (subsequently Multiplicisphaeridium) micropilare Cramer, 1970, an acritarch species, according to Ye Xiaorong (1984, p.42).  This combination was not validly published in Downie (1959, p.60 and 1963, p.641) and Downie and Sarjeant (1963, p.90), since these authors did not fully reference the basionym.  Age: Silurian (Late Llandovery-Late Ludlow).

Parent: Baltisphaeridium