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Cribroperidinium complexum
Cribroperidinium complexum Bailey, 1993
Holotype: Bailey, 1993, pl.1, figs.2-3
Locus typicus: Norsk Hydro Norwegian Well 7120/12-2, at 1838m (Hekkingen Formation), Northern Atlantic
Stratum typicum: Kimmeridgian
Original diagnosis: Bailey, 1993, p.219-220
A large species of Cribroperidinium, hypocyst broadly rounded, epicyst merging into a pronounced apical horn which is terminated by a complex apicular structure, composed of interlinking trabeculate elements. Sexiform gonyaulacoid paratabulation expressed by parasutural crests or ridges, which often develop proximate vacuoles and/or distal trabeculae. Parasutural features are more strongly expressed antapically and along the paracingulum. Surface of autophragm scabrate to granulate. Precingular archaeopyle, type P (3").
Size range. 80 Ám-130 Ám overall length (holotype 122 Ám x 98 Ám.
Remarks. The apical horn is variably developed (compare Pl. 1, Figs 2 and 6). It is always surmounted by a complex apicular structure composed of trabeculate elements. No intratabular ridges or crests have been observed and there are no small dorsal intercalary plates (Pl. 1, Fig 9).
Affinities:
Bailey, 1993, p.220: Cribroperidinium complexum is easily identified by its characterishc apical horn, style of parasutural ornament and large size. Cribroperidinium gigas (Raynaud) Helenes 1984 is often of similar overall shape, but the horn, although long and terminated by a solid extension, is not ornamented by trabeculate elements. In addihon, C. gigas has a thicker wall, ornamented by spines Cribroperidinium longicorne (Downie) Lentin and Williams 1985 is usually smaller, with a thin wall and poorly defined paratabulation.
Holotype: Bailey, 1993, pl.1, figs.2-3
Locus typicus: Norsk Hydro Norwegian Well 7120/12-2, at 1838m (Hekkingen Formation), Northern Atlantic
Stratum typicum: Kimmeridgian
Original diagnosis: Bailey, 1993, p.219-220
A large species of Cribroperidinium, hypocyst broadly rounded, epicyst merging into a pronounced apical horn which is terminated by a complex apicular structure, composed of interlinking trabeculate elements. Sexiform gonyaulacoid paratabulation expressed by parasutural crests or ridges, which often develop proximate vacuoles and/or distal trabeculae. Parasutural features are more strongly expressed antapically and along the paracingulum. Surface of autophragm scabrate to granulate. Precingular archaeopyle, type P (3").
Size range. 80 Ám-130 Ám overall length (holotype 122 Ám x 98 Ám.
Remarks. The apical horn is variably developed (compare Pl. 1, Figs 2 and 6). It is always surmounted by a complex apicular structure composed of trabeculate elements. No intratabular ridges or crests have been observed and there are no small dorsal intercalary plates (Pl. 1, Fig 9).
Affinities:
Bailey, 1993, p.220: Cribroperidinium complexum is easily identified by its characterishc apical horn, style of parasutural ornament and large size. Cribroperidinium gigas (Raynaud) Helenes 1984 is often of similar overall shape, but the horn, although long and terminated by a solid extension, is not ornamented by trabeculate elements. In addihon, C. gigas has a thicker wall, ornamented by spines Cribroperidinium longicorne (Downie) Lentin and Williams 1985 is usually smaller, with a thin wall and poorly defined paratabulation.