Spiniferites membranosus (Archangelsky, 1969) Lentin and Williams, 1973

Originally Hystrichosphaera, subsequently (and now Spiniferites.
Taxonomic senior synonym: Hystrichosphaera (as and now Achomosphaera) crassipellis, according to Quattrocchio and Sarjeant (1996, p.116).

Holotype: Archangelsky, 1969, pl.3, figs.1-3
Age: Late Eocene