Hystrichosphaeridium placacanthum

"placacanthum" Deflandre and Cookson, 1955, p.276–277, pl.9, figs.1–3.  Emendation: May, 1980, p.68, as Systematophora placacantha.  Holotype: Deflandre and Cookson, 1955, pl.9, figs.1–2; Fauconnier and Masure, 2004, pl.76, figs.14–16.  NOW Cleistosphaeridium.  Originally Hystrichosphaeridium, subsequently Baltisphaeridium (Appendix A), thirdly Impletosphaeridium, fourthly Systematophora, fifthly (and now) Cleistosphaeridium.  Taxonomic junior synonyms: Baltisphaeridium (now Impletosphaeridium) panniforme, according to Sarjeant (1984b, p.86–87) — however, Eaton et al. (2001, p.191) retained Baltisphaeridium panniforme; Systematophora ancyrea, according to Stover and Evitt (1978, p.84) — however, Lentin and Williams (1981, p.272) retained Systematophora ancyrea.  Age: Miocene.

Parent: Hystrichosphaeridium