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Gonyaulacysta pyrum
Gonyaulacysta pyra (Drugg, 1967) Eisenack, 1967
Now Cribroperidinium?. Originally Gonyaulax, subsequently Gonyaulacysta, thirdly (and now) Cribroperidinium?.
Holotype: Drugg, 1967, pl.1, fig.17; Jan du Chêne et al., 1986, pl.27, figs.3-5
Locus typicus: Escapado Canyon, California
Stratum typicum; Maastrichtian-Danian
Original diagnosis: Drugg, 1967, p.14: Gonyaulax pyra
Test somewhat pear-shaped. Wall thin, faintly punctate. Apical horn short, truncate, ending in a few short projections. Sutures low and inconspicuous, slightly denticulate. The tabulation cannot usually be determined in its entirety on any single specimen and indeed has not been determined with any high degree of confidence. The apparent tabulation composited from numerous specimens is shown on plate 9, figure 6a--b. It seems to be 3", 6"", 6"""", 1p, 1"""". The girdle is distinct but the longitudinal furrow is much less prominent. The archeopyle is formed by the separation of precingular plate 4".
Dimensions: Holotype 74 Ám wide and 86 Ám high; range 66 to 89 Ám wide, 83 to 100 Ám high.
Affinities:
Drugg, 1967, p.14: Gonyaulax pyra
This species is similar in overall appearance to several previously described species such as Gonyaulax scotti Cookson and Eisenack 1958, G. orthoceras Eisenack 1958, and G. diaphanis Cookson and Eisenack 1958. It differs from the latter in lacking spiny ledges bordering the plates and girdle and in lacking intercalary plates on the epitheca. It differs from G. scotti in that it has a much thinner wall and lacks delicate processes forming a membrane. It differs from G. orthoceras most noticeably in that it has a shorter apical horn, a thinner wall, and less prominent sutures. In addition plate 3" forms the archeopyle in G. orthoceras (Gorka, 1963 p. 30) whereas it is plate 4" on the Dos Palos species. Gonyaulax pyra differs from G. tenuitabulata Gerlach 1961 in tabulation, in possessing slightly denticulate sutures, and in having a punctate as opposed to a granulate wall.
Now Cribroperidinium?. Originally Gonyaulax, subsequently Gonyaulacysta, thirdly (and now) Cribroperidinium?.
Holotype: Drugg, 1967, pl.1, fig.17; Jan du Chêne et al., 1986, pl.27, figs.3-5
Locus typicus: Escapado Canyon, California
Stratum typicum; Maastrichtian-Danian
Original diagnosis: Drugg, 1967, p.14: Gonyaulax pyra
Test somewhat pear-shaped. Wall thin, faintly punctate. Apical horn short, truncate, ending in a few short projections. Sutures low and inconspicuous, slightly denticulate. The tabulation cannot usually be determined in its entirety on any single specimen and indeed has not been determined with any high degree of confidence. The apparent tabulation composited from numerous specimens is shown on plate 9, figure 6a--b. It seems to be 3", 6"", 6"""", 1p, 1"""". The girdle is distinct but the longitudinal furrow is much less prominent. The archeopyle is formed by the separation of precingular plate 4".
Dimensions: Holotype 74 Ám wide and 86 Ám high; range 66 to 89 Ám wide, 83 to 100 Ám high.
Affinities:
Drugg, 1967, p.14: Gonyaulax pyra
This species is similar in overall appearance to several previously described species such as Gonyaulax scotti Cookson and Eisenack 1958, G. orthoceras Eisenack 1958, and G. diaphanis Cookson and Eisenack 1958. It differs from the latter in lacking spiny ledges bordering the plates and girdle and in lacking intercalary plates on the epitheca. It differs from G. scotti in that it has a much thinner wall and lacks delicate processes forming a membrane. It differs from G. orthoceras most noticeably in that it has a shorter apical horn, a thinner wall, and less prominent sutures. In addition plate 3" forms the archeopyle in G. orthoceras (Gorka, 1963 p. 30) whereas it is plate 4" on the Dos Palos species. Gonyaulax pyra differs from G. tenuitabulata Gerlach 1961 in tabulation, in possessing slightly denticulate sutures, and in having a punctate as opposed to a granulate wall.