Xanthidium malleoferum White, 1842

Now Achomosphaera?. Originally Xanthidium, subsequently Hystrichosphaeridium, thirdly Baltisphaeridium (an acritarch genus), fourthly (and now ) Achomosphaera?. Holotype: White, 1842, pl.4, div.3, fig.7; Sarjeant, 1991, fig.4.6
Age: Late Cretaceous