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Rhynchodiniopsis serrata
Rhynchodiniopsis serrata (Cookson and Eisenack, 1958) Jan du Chêne et al., 1985
Originally Gonyaulax, subsequently Gonyaulacysta, thirdly Hystrichogonyaulax, fourthly (and now) Rhynchodiniopsis.
Holotype: Cookson and Eisenack, 1958, pl.3, fig.2; Jan du Chêne et al., 1986, pl.99, figs.3-4
Locus typicus: Omatia, Papua
Stratum typicum: Late Jurassic-?Neocomian
Original description: Cookson and Eisenack, 1958, p. 34: Gonyaulax serrata
All the available specimens are flattened and in consequence polygonal in outline. The plates of both epitheca and hypotheca are relatively large and the transverse girdle is helicoid; the longitudinal furrow extends to the antapical plate. The epitheca is terminated by a very short conical process which is covered with spiny projections and the sutures of the plates and margins of the furrow are ornamented with rather broad comb-like ledges, the teeth of which are either rounded, knob-like or occasionally slightly bifurcate. The exact tabulation could not be determined. However, G. serrata is a readily recognizable form. Dimensions: Type - 109 x 100 µm. Another specimen 100 x 94 µm; spines c. 2.5-6 µm long.
Affinities:
Cookson and Eisenack, 1958, p. 34: Gonyaulax serrata
Gonyaulax serrata seems to be closely related to G. cladophora Defl. from the French Oxfordian. However, it differs from that species in the simpler form and more even length of the spines ornamenting the shell, and in the form of the apical prominence. According to the original diagnosis, G. cladophora always has a distinct tubular apical horn. In G. serrata, on the other hand, only a short blunt apical prominence surmounted by a few short spines is developed.
Originally Gonyaulax, subsequently Gonyaulacysta, thirdly Hystrichogonyaulax, fourthly (and now) Rhynchodiniopsis.
Holotype: Cookson and Eisenack, 1958, pl.3, fig.2; Jan du Chêne et al., 1986, pl.99, figs.3-4
Locus typicus: Omatia, Papua
Stratum typicum: Late Jurassic-?Neocomian
Original description: Cookson and Eisenack, 1958, p. 34: Gonyaulax serrata
All the available specimens are flattened and in consequence polygonal in outline. The plates of both epitheca and hypotheca are relatively large and the transverse girdle is helicoid; the longitudinal furrow extends to the antapical plate. The epitheca is terminated by a very short conical process which is covered with spiny projections and the sutures of the plates and margins of the furrow are ornamented with rather broad comb-like ledges, the teeth of which are either rounded, knob-like or occasionally slightly bifurcate. The exact tabulation could not be determined. However, G. serrata is a readily recognizable form. Dimensions: Type - 109 x 100 µm. Another specimen 100 x 94 µm; spines c. 2.5-6 µm long.
Affinities:
Cookson and Eisenack, 1958, p. 34: Gonyaulax serrata
Gonyaulax serrata seems to be closely related to G. cladophora Defl. from the French Oxfordian. However, it differs from that species in the simpler form and more even length of the spines ornamenting the shell, and in the form of the apical prominence. According to the original diagnosis, G. cladophora always has a distinct tubular apical horn. In G. serrata, on the other hand, only a short blunt apical prominence surmounted by a few short spines is developed.