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Gonyaulacysta aptiana

Gonyaulacysta aptiana (Deflandre, 1935, p.231, pl.5, fig.10; pl.8, figs.7–10) Millioud, 1969, p.428. Emendation: Sarjeant, 1982b, p.36–37, as Rhynchodiniopsis aptiana.

Combination illegitimate: this is the "type species" of the earlier generic name Rhynchodiniopsis.
NOW Rhynchodiniopsis. Originally (and now) Rhynchodiniopsis, subsequently Gonyaulacysta.
Taxonomic junior synonym: Gonyaulacysta fimbriata, according to Below (1981a, p.118) — however, Sarjeant (1982b, p.35) retained Gonyaulacysta (as Rhynchodiniopsis) fimbriata.
This combination was not validly published in Sarjeant (1966b, p.130), since that author did not fully reference the basionym.

Holotype: Holotype: Deflandre, 1935, pl.5, fig.10; pl.8, figs.7-9; Deflandre, 1936, pl.7, figs.2-4
Paratypes: Deflandre, 1936
Locus typicus: Provence, France
Stratum typicum: Senonian
Translation Deflandre, 1935: LPP

Original description: Deflandre, 1935, p. 231; improved description Deflandre, 1936, p. 180: Rhynchodiniopsis aptiana
Diagnosis (Deflandre, 1936): In frontal view, the theca is clearly hexagonal,the upper part mounted by a strongly cylindrical or subcylindrical horn. The epitheca and hypotheca are of approximately equal size. The epitheca has the form of a truncate pyramid, the upper plane consisting of two apical plates, one of which bears the horn. The horn, as far as one can judge, consists of a single piece, and stems from the second apical plate (the first apical is formed by the top of the longitudinal furrow). A very small, invariable, rectangular intercalary plate connects the third apical and the third pre-equatorial, which is situated dorsally. The six pre-equatorials are connected by sutures bearing strong, aliform, denticulate crests, ending towards the transverse furrow in a strong, often crooked thorn. The tabulation of the hypotheca is less well known. There seem to be two, nearly equal antapicals, about as large as the second and third apicals, and probably six post-equatorial plates, trapezoidal, like the pre-equatorials. The sutures are evenly provided with crests, and thorns where they meet the transverse furrow. The latter is laevorotatory, and enclosed by two strongly denticulate crests. It consists of several (six?) plates, of which the sutures standing at a right angle to the furrow sometimes cause narrowings, which give the plates a hexagonal appearance. Sometimes there seems to be a resemblance with the equatorial plates of Hystrichosphaera. The longitudinal furrow is well-developed and seems to extend from apex to antapex. The membrane is reticulate and often granulate or chagrinate, and yellowish.
Dimensions: Total length 90-100 µm, total width 60-75 µm.
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