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Gonyaulacysta longicornis
Gonyaulacysta? longicornis (Downie 1957) Sarjeant 1969
Now Cribroperidinium?. Originally Gonyaulax, subsequently Gonyaulacysta, thirdly Gonyaulacysta?, fourthly Millioudodinium, fifthly (and now) Cribroperidinium?. Sarjeant, 1966, questionably included the species in Gonyaulacysta.
Stover and Evitt, 1978, considered this to be a provisionally accepted species of Gonyaulacysta.
This combination was not validly published in Sarjeant, 1966, since that author did not fully reference the basionym.
Holotype: Downie, 1957, pl.20, fig.8, text-figs.2a-b; Jan du Chêne et al., 1986, pl.30, fig.1
Locus typicus: Dorset, England
Stratum typicum: Late Kimmeridgian
Original diagnosis: Downie, 1957, p. 420: Gonyaulax longicornis
The test is approximatelly equidimensional and has a very long apical horn with a solid tip developed from plate 1". The length of the horn is about one-third of the total length. Fine striations run round it near the base. The spiral equatorial furrow divides the test into roughly equal parts. The longitudinal furrow is wide and less distinct. The tabulation is 4", 6"", 6""", 1"""", the plates being flat or slightly convex. The sutures have low flanges, at times very faint, and bear tiny spines that are prominent only where the sutures join.
Dimensions of holotype: length 92 µm, breadth 59 µm, length of horn 36 µm.
Affinities:
Downie, 1957, p. 420: Gonyaulax longicornis
This species was particularly common at Setchey where several well-preserved specimens were found. The long polar horn and low sutures are not associated in any other species of Gonyaulax but the general form may be compared with Palaeoperidinium nudum.
Now Cribroperidinium?. Originally Gonyaulax, subsequently Gonyaulacysta, thirdly Gonyaulacysta?, fourthly Millioudodinium, fifthly (and now) Cribroperidinium?. Sarjeant, 1966, questionably included the species in Gonyaulacysta.
Stover and Evitt, 1978, considered this to be a provisionally accepted species of Gonyaulacysta.
This combination was not validly published in Sarjeant, 1966, since that author did not fully reference the basionym.
Holotype: Downie, 1957, pl.20, fig.8, text-figs.2a-b; Jan du Chêne et al., 1986, pl.30, fig.1
Locus typicus: Dorset, England
Stratum typicum: Late Kimmeridgian
Original diagnosis: Downie, 1957, p. 420: Gonyaulax longicornis
The test is approximatelly equidimensional and has a very long apical horn with a solid tip developed from plate 1". The length of the horn is about one-third of the total length. Fine striations run round it near the base. The spiral equatorial furrow divides the test into roughly equal parts. The longitudinal furrow is wide and less distinct. The tabulation is 4", 6"", 6""", 1"""", the plates being flat or slightly convex. The sutures have low flanges, at times very faint, and bear tiny spines that are prominent only where the sutures join.
Dimensions of holotype: length 92 µm, breadth 59 µm, length of horn 36 µm.
Affinities:
Downie, 1957, p. 420: Gonyaulax longicornis
This species was particularly common at Setchey where several well-preserved specimens were found. The long polar horn and low sutures are not associated in any other species of Gonyaulax but the general form may be compared with Palaeoperidinium nudum.