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Lejeunia cretacea
Lejeunia? cretacea (Pocock, 1962, p.80, pl.14, figs.219–221 ex Davey, 1970, p.359, pl.2, fig.4) Brideaux, 1971, p.86. Emendation: Harding, 1990a, p.44, as Palaeoperidinium cretaceum.
Combination illegitimate since the generic name Lejeunia is illegitimate.
Now Palaeoperidinium. Originally (and now) Palaeoperidinium, subsequently Astrocysta, thirdly Lejeunia (an illegitimate generic name), fourthly Subtilisphaera.
Tax. sr. synonym of Palaeoperidinium amplum (Harland, 1973) Lentin and Williams, 1976, according to Harker and Sarjeant in Harker et al., 1990.
Tax. sr. synonym of Palaeoperidinium manumcooksoniae (Corradini, 1973) Lentin and Williams, 1976, according to Lentin and Williams, 1976.
At the time of the transfer, Brideaux, 1971, questionably included this species in Lejeunia.
Holotype: Pocock, 1962, pl.14, figs.219-221
Paratype: Pocock, 1963
Locus typicus: Imperial Murrey Test Hole No.6, W Canada
Stratum typicum: Aptian-Albian
Original diagnosis: Pocock 1962, p. 80: Palaeoperidinium cretaceum
Theca longer than it is broad, ellipsoidal; epitheca long, conical tapering to a point and may or may not be surmounted by a solid apical horn; equatorial girdle well developed, helicoid; hypotheca more or less dome shaped, terminated by two hypothecal spines, one always being longer than the other. Thecal wall thin and transparent, pale yellow or colourless, with no visible system of plates; theca is either scabrate or finely granulose and, in well preserved specimens, usually contains yellow green rounded crystalline bodies; spherical cysts have been observed with the thecae of some specimens.
Dimensions: Range: Length: 81-95 Ám; Breadth: 50-69 Ám; Length of longer hypothecal spine: 12-25 Ám; Length of shorter hypothecal spine: 4-10 Ám.
Supplemental description: Brideaux, 1971, p.86
Dinoflagellate cyst; outline pentagonal or rounded-pentagonal; apex tapering to a rounded or slightly pointed, short apical prominence; antapex with two antapical horns, the left antapical horn generally slightly or distinctly longer. Epitract slightly longer or nearly equal in length to the hypotract; hypotract tapel-ing slightly towards the antapex, flattened between antapical horns. Cyst wall thin; occasional specimens suggest a two-layered wall with the inner layer very closely appressed to the outer layer; no specimens have shown a definite separation into capsule and outer wall layer as in cavate dinoflagellate forms. Tabulation pattern not developed; occasional specimens bear incomplete traces of a possible tabulation pattern, expressed as faint lines on the cyst wall; these are generally overshadowed by a proliferation of such traces in completely random patterns. Cingulum present, often indistinct, outlined by narrow folds or low ridges; sulcus not noted. No distinct evidence of archeopyle structure noted; some specimens show and incomplete outline suggestive of an intercalary plate, but no rupture has been observed in thousands of specimens; some specimens have the apical portion broken off or show an incomplete rupture along the cingulum; these specimens appear to be exhibiting mechanical breakage rather than archeopyle formation.
Dimensions: On 42 measured specimens: length, 63--119 Ám; width, 41--88 Ám; apical horn length, 5-18 Ám; length of left antapical horn, 12--29 Ám; length of right antapical horn, 3--17 Ám. A total of 90 specimens recorded, many more observed.
Combination illegitimate since the generic name Lejeunia is illegitimate.
Now Palaeoperidinium. Originally (and now) Palaeoperidinium, subsequently Astrocysta, thirdly Lejeunia (an illegitimate generic name), fourthly Subtilisphaera.
Tax. sr. synonym of Palaeoperidinium amplum (Harland, 1973) Lentin and Williams, 1976, according to Harker and Sarjeant in Harker et al., 1990.
Tax. sr. synonym of Palaeoperidinium manumcooksoniae (Corradini, 1973) Lentin and Williams, 1976, according to Lentin and Williams, 1976.
At the time of the transfer, Brideaux, 1971, questionably included this species in Lejeunia.
Holotype: Pocock, 1962, pl.14, figs.219-221
Paratype: Pocock, 1963
Locus typicus: Imperial Murrey Test Hole No.6, W Canada
Stratum typicum: Aptian-Albian
Original diagnosis: Pocock 1962, p. 80: Palaeoperidinium cretaceum
Theca longer than it is broad, ellipsoidal; epitheca long, conical tapering to a point and may or may not be surmounted by a solid apical horn; equatorial girdle well developed, helicoid; hypotheca more or less dome shaped, terminated by two hypothecal spines, one always being longer than the other. Thecal wall thin and transparent, pale yellow or colourless, with no visible system of plates; theca is either scabrate or finely granulose and, in well preserved specimens, usually contains yellow green rounded crystalline bodies; spherical cysts have been observed with the thecae of some specimens.
Dimensions: Range: Length: 81-95 Ám; Breadth: 50-69 Ám; Length of longer hypothecal spine: 12-25 Ám; Length of shorter hypothecal spine: 4-10 Ám.
Supplemental description: Brideaux, 1971, p.86
Dinoflagellate cyst; outline pentagonal or rounded-pentagonal; apex tapering to a rounded or slightly pointed, short apical prominence; antapex with two antapical horns, the left antapical horn generally slightly or distinctly longer. Epitract slightly longer or nearly equal in length to the hypotract; hypotract tapel-ing slightly towards the antapex, flattened between antapical horns. Cyst wall thin; occasional specimens suggest a two-layered wall with the inner layer very closely appressed to the outer layer; no specimens have shown a definite separation into capsule and outer wall layer as in cavate dinoflagellate forms. Tabulation pattern not developed; occasional specimens bear incomplete traces of a possible tabulation pattern, expressed as faint lines on the cyst wall; these are generally overshadowed by a proliferation of such traces in completely random patterns. Cingulum present, often indistinct, outlined by narrow folds or low ridges; sulcus not noted. No distinct evidence of archeopyle structure noted; some specimens show and incomplete outline suggestive of an intercalary plate, but no rupture has been observed in thousands of specimens; some specimens have the apical portion broken off or show an incomplete rupture along the cingulum; these specimens appear to be exhibiting mechanical breakage rather than archeopyle formation.
Dimensions: On 42 measured specimens: length, 63--119 Ám; width, 41--88 Ám; apical horn length, 5-18 Ám; length of left antapical horn, 12--29 Ám; length of right antapical horn, 3--17 Ám. A total of 90 specimens recorded, many more observed.