Hystrichosphaera membranosa

"membranosa" Archangelsky, 1969b, p.197,199, pl.3, figs.1–4.  Holotype: Archangelsky, 1969b, pl.3, figs.1–3.  Originally Hystrichosphaera, subsequently Spiniferites.  Taxonomic senior synonym: Hystrichosphaera (as and now Achomosphaera) crassipellis, according to Quattrocchio and Sarjeant (1996, p.116).  Age: late Eocene.

Parent: Hystrichosphaera