Baltisphaeridium brevispinosum subsp. callosum Appendix A

subsp. callosum (Sannemann, 1955, p.325–326, pl.1, figs.1–4,7; pl.3, figs.2–5,10; pl.4, figs.3–9; pl.6, figs.11–12; text-figs.2a–d) Fensome et al., 1990, p.87.  Holotype: Sannemann, 1955, pl.4, fig.3.  Originally Hystrichosphaeridium brevispinosum subsp. callosum, subsequently Buedingiisphaeridium brevispinosum subsp. callosum (combination not validly published, Appendix A), thirdly (and now) Baltisphaeridium brevispinosum subsp. callosum.  This combination was not validly published in Downie and Sarjeant (1963 p.90), since these authors did not fully reference the basionym, nor was it validly published in Eisenack et al. (1973, p.79–80), since these authors did not give a clear indication of taxonomic rank.  Le Herissé in Ribecai and Tongiorgi (1999, p.124) considered this taxon and Baltisphaeridium brevispinosum subsp. castaneoides to be "... related to mazuelloids or muellerisphaerids (mineralized microfossils)" and not conspecific with Hystrichosphaeridium (now Pachysphaeridium) brevispinosum, but no new taxonomic assignations were proposed.  We feel that, although the species has been transferred to Pachysphaeridium, since this Index does not treat acritarchs or mineralized microfossils in detail, it would be inappropriate for us to make taxonomic proposals here; hence we leave two subspecies (and the autonym) "in limbo".  Age: Devonian (late Givetian).

Parent: Baltisphaeridium brevispinosum_Appendix A