crassipellis (Deflandre and Cookson, 1955, p.265, pl.6, figs.2-3; text-fig.20) Stover and Evitt, 1978, p.138. Holotype: Deflandre and Cookson, 1955, pl.6, figs.2-3. Originally Hystrichosphaera, subsequently Spiniferites, thirdly (and now) Achomosphaera. Taxonomic junior synonyms: Achomosphaera recurvata and Hystrichosphaera (subsequently Spiniferites) membranosa, according to Quattrocchio and Sarjeant (1996, p.116). May (1980, p.64) considered Achomosphaera sagena to be a possible taxonomic junior synonym of this species. Age: Early Eocene.