Gonyaulacysta jurassica var. longicornis (Deflandre, 1939a, p.171, pl.6, fig.6) Downie and Sarjeant, 1965, p.115. Emendation: Sarjeant, 1982b, p.31, as Gonyaulacysta jurassica subsp. adecta var. longicornis.

Originally Gonyaulax jurassica var. longicornis (Motile stage), subsequently Gonyaulacysta jurassica var. longicornis, thirdly Gonyaulacysta jurassica subsp. longicornis, fourthly (and now) Gonyaulacysta jurassica subsp. adecta var. longicornis.
Taxonomic junior synonym: Gonyaulax (as Gonyaulacysta) jurassica subsp. brevis, according to Sarjeant (1982b, p.31).

Holotype: Deflandre, 1939a, pl.6, fig.6; Jan du Chêne et al., 1986a, pl.37, figs.7-8.
Age: Oxfordian.