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Nannobarbophora walldalei
Nannobarbophora walldalei Head 1996;
Synonyms:
Nannobarbophora sp. cf. N. barbata Habib and Knapp, 1982; HEAD, 1994a, p.292, table 1.
Acritarch sp. B. VERSTEEGH AND ZONNEVELD, 1994, p. 197, pl. I, figs. 3,6.
Holotype: Head 1996: Figure 17.1-17.3.
Type locality: Ocean Drilling Program Leg 104, Hole 644A, Voring Basin, Norwegian Sea.
Stratum typicum: lower upper Pliocene
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Diagnosis: Head 1996, p. 565-567
A large species of Nannobarbophora whose numerous tapering, distally closed processes bear small spinules on surface, their distribution usually concentrated over distal half. Process stems mostly solid but may be hollow proximally. Process bases usually fibrous and proximally expanded. Surface of central body more or less smooth under light microscope.
Description: Head 1996, p. 565-567
Central body ca. 21 to 33 ,um in maximum diameter and spherical to ovoidal, bearing numerous tapering, distally closed processes ca.2.5 to 6.0,um in length. Each process has small spinules (visible under light microscopy) on surface, their distribution usually concentrated over distal half. Process stems mostly solid but may be hollow proximally. Process bases usually fibrous and proximally expanded (as for holotype), but apparently solid and non-expanded on occasional specimens. Surface of central body more or less smooth under light microscope but scattered granules or spinules may be detected under SEM. Wall of central body very thin (0.3 Ám or less) and frequently crumpled. Aperture is a simple tear.
Dimensions: Holotype: central body, 28 x 25Ám; average process length, 3.7 Ám. Range: Norwegian Sea (sample ODP 104-644A-32-2; 135-137 cm; based on 10 specimens): central body maximum diameter, 21(25.0)32Ám; average process length, 2.9(4.3)5.0 Ám. Ludham Borehole (based on 22 specimens): central body maximum diameter, 23(28.6)33Ám; average process length, 2.9(4.5)5.7Ám.
Comparison.--Nannobarbophora barbata Habib and Knapp, 1982 and N. pistilla Habib and Knapp, 1982, both described from the Cretaceous of the western North Atlantic, are smaller (central body diameter 5.5 to 8.5Ám for N. barbata and 6.0 to 8.4Ám for N. pistilla; process length 1.1 to 2.0 for N. barbata and 0.7 to 2.6Ám for N. pistilla. Nannobarbophora walldalei can have fibrous process bases not recorded for N. barbata or N. pistilla.
Other records: Lower upper Pliocene of the Norwegian Sea (this study); the upper Pliocene of eastern England (as Nannobarbophora sp. cf. N. barbata, in Head, 1994a); upper Pliocene of Italy (as Acritarch sp. B in Versteegh and Zonneveld, 1994) and lower Pliocene through lower Pleistocene of DSDP Hole 61 OA, eastern North Atlantic (M. J. Head, unpublished data).
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Description: Versteegh and Zonneveld 1994, p. 197: Acritarch sp. B
Subspherical skolochorate forms with a more or less regular process distribution on the furthermore smooth body surface. The processes are solid and their diameter decreases distally. They nearly always have scattered granules on their surface. These granules are best developed on the upper half of the spines. On the body
surface of specimens a pattern of lines which resembles the pattern of plate sutures on dinoflagellate cysts is visible. An archaeopyle or other consistently occurring opening in the body wall has not been evidenced.
Size: Body diameter ¦ 20Ám; spine length # 5Ám (n =4)
Occurrence: Frequent to common in the sediments of the Singa section. Pliocene.
Comparison: This type closely resembles Operculodinium eirikianum but differs in ( 1 ) lacking an archaeopyle and a granulate body surface, and (2) having a smaller size and shorter spines compared to the body diameter.
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Synonyms:
Nannobarbophora sp. cf. N. barbata Habib and Knapp, 1982; HEAD, 1994a, p.292, table 1.
Acritarch sp. B. VERSTEEGH AND ZONNEVELD, 1994, p. 197, pl. I, figs. 3,6.
Holotype: Head 1996: Figure 17.1-17.3.
Type locality: Ocean Drilling Program Leg 104, Hole 644A, Voring Basin, Norwegian Sea.
Stratum typicum: lower upper Pliocene
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Diagnosis: Head 1996, p. 565-567
A large species of Nannobarbophora whose numerous tapering, distally closed processes bear small spinules on surface, their distribution usually concentrated over distal half. Process stems mostly solid but may be hollow proximally. Process bases usually fibrous and proximally expanded. Surface of central body more or less smooth under light microscope.
Description: Head 1996, p. 565-567
Central body ca. 21 to 33 ,um in maximum diameter and spherical to ovoidal, bearing numerous tapering, distally closed processes ca.2.5 to 6.0,um in length. Each process has small spinules (visible under light microscopy) on surface, their distribution usually concentrated over distal half. Process stems mostly solid but may be hollow proximally. Process bases usually fibrous and proximally expanded (as for holotype), but apparently solid and non-expanded on occasional specimens. Surface of central body more or less smooth under light microscope but scattered granules or spinules may be detected under SEM. Wall of central body very thin (0.3 Ám or less) and frequently crumpled. Aperture is a simple tear.
Dimensions: Holotype: central body, 28 x 25Ám; average process length, 3.7 Ám. Range: Norwegian Sea (sample ODP 104-644A-32-2; 135-137 cm; based on 10 specimens): central body maximum diameter, 21(25.0)32Ám; average process length, 2.9(4.3)5.0 Ám. Ludham Borehole (based on 22 specimens): central body maximum diameter, 23(28.6)33Ám; average process length, 2.9(4.5)5.7Ám.
Comparison.--Nannobarbophora barbata Habib and Knapp, 1982 and N. pistilla Habib and Knapp, 1982, both described from the Cretaceous of the western North Atlantic, are smaller (central body diameter 5.5 to 8.5Ám for N. barbata and 6.0 to 8.4Ám for N. pistilla; process length 1.1 to 2.0 for N. barbata and 0.7 to 2.6Ám for N. pistilla. Nannobarbophora walldalei can have fibrous process bases not recorded for N. barbata or N. pistilla.
Other records: Lower upper Pliocene of the Norwegian Sea (this study); the upper Pliocene of eastern England (as Nannobarbophora sp. cf. N. barbata, in Head, 1994a); upper Pliocene of Italy (as Acritarch sp. B in Versteegh and Zonneveld, 1994) and lower Pliocene through lower Pleistocene of DSDP Hole 61 OA, eastern North Atlantic (M. J. Head, unpublished data).
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Description: Versteegh and Zonneveld 1994, p. 197: Acritarch sp. B
Subspherical skolochorate forms with a more or less regular process distribution on the furthermore smooth body surface. The processes are solid and their diameter decreases distally. They nearly always have scattered granules on their surface. These granules are best developed on the upper half of the spines. On the body
surface of specimens a pattern of lines which resembles the pattern of plate sutures on dinoflagellate cysts is visible. An archaeopyle or other consistently occurring opening in the body wall has not been evidenced.
Size: Body diameter ¦ 20Ám; spine length # 5Ám (n =4)
Occurrence: Frequent to common in the sediments of the Singa section. Pliocene.
Comparison: This type closely resembles Operculodinium eirikianum but differs in ( 1 ) lacking an archaeopyle and a granulate body surface, and (2) having a smaller size and shorter spines compared to the body diameter.
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