From Fensome et al., 2019:
Gonyaulacysta jurassica ssp. adecta var. longicornis (Deflandre, 1938, p.171, pl.6, fig.6) Downie and Sarjeant, 1965, p.115. Emendation: Sarjeant, 1982b, p.31, as Gonyaulacysta jurassica subsp. adecta var. longicornis. Holotype: Deflandre, 1938, pl.6, fig.6; Jan du Chêne et al., 1986a, pl.37, figs.7–8. Originally Gonyaulax jurassica var. longicornis (Appendix B), 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). Age: Oxfordian.

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