Gonyaulax crassicornuta Klement, 1960; Emendation: Sarjeant, 1984a, p.158–160, as Rhynchodiniopsis crassicornuta.

Now Gonyaulacysta?. Originally Gonyaulax, subsequently Gonyaulacysta, thirdly (and now) Gonyaulacysta?, fourthly Rhynchodiniopsis.

Holotype: Klement, 1960, pl.5, fig.1; Sarjeant, 1984, pl.2, figs.1-2; text-fig.2; Jan du Chene et al., 1986, pl.45, figs.1-4
Age: Early Kimmeridgian