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