Spinidinium "montanaensis" (Harland, 1977a, p.184–185, pl.25, figs.4,6–7,10–12) Lentin and Williams, 1981, p.10.

Combination illegitimate: the generic name Alterbia is illegitimate.
NOW Alterbidinium. Originally Deflandrea, subsequently Spinidinium, thirdly Alterbia (combination illegitimate), fourthly (and now) Alterbidinium.

Holotype: Harland, 1977a, pl.25, fig.4.
Age: late Campanian–Maastrichtian.