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Barssidinium olymposum
Barssidinium olymposa, Warny et Wrenn, 1997 (Plate IX, I -6)
Holotype: Warny et Wrenn, 1997: Plate IX, 3 and 4
Type locality: Bou Regreg S Core, Sale, Riffian Corridor, Morocco.
Stratum typicum: Messinian
Stratigraphic range: Miocene, samples B94 (162.5 m)-S 17 (18.54 m) ( Fig. 2).
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Original description: [Warny et Wrenn, 1997, p. 299, 301]:
Diagnosis:
A spherical to ovoidal shaped species of Barssidinium bearing numerous nontabular processes primarily around the cyst margin.
Processes are flared distally. The distal termination of these processes is special in that each is usually a hemispherical bowl.
The operculum of the intercalary ( Type 2a) archeopyle is usually not free. The archeopyle is the only indication of paratabulation on the cyst.
Description:
Processes: Numerous nontabular processes with distal ends resembling the Olympic bowl. Process length varies from 6.8 to 11.9 µm with a mean of 8.6 µm. The ratio of the equatorial diameter of the central body and the length of processes is about 1/5 to 1/7. Processes are usually more abundant around the margin of the cyst.
Shape: Elliptical to rounded in plane view, and dorsoventrally compressed.
Phragma: The cysts are bound by an autophragm or two closely appressed wall layers. The surface is smooth to granulate.
Archeopyle: We assume that the archeopyle of B. olymposa is intercalary ( Type 2a) because the overall aspect of the cyst, and the large size and position (sitting low on the dorsal surface) of the archeopyle resemble those characteristics on other species of Barssidinium (Lentin et al., 1994). Its location is indicated on most specimens only by a slight opening of its sutures. On some specimens, the large operculum may resemble a precingular Type P archeopyle. The operculum is not free and may be adnate anteriorly.
Paratabulation: Paratabulation is indicated only by the Type 2a intercalary archeopyle.
Paracingulum: Not evident.
Parasulcus: Not discernible.
Dimensions:
Holotype: central body diameter 68.0 µm; length of process 5.1-8.5 µm. Mean (x) and extreme values for n= 11: central body diameter 47.6-(55.1)-68.0 µm; length of process 6.8-(8.6)-ll.9 µm.
Affinities/Comparison:
Barssidinium olymposa is of the same age and quite similar to Barssidinium soucouyantae (De Verteuil and Norris, 1992). However, its processes are totally different and the operculum often is not free. Specimens of S. olymposa may resemble some species of Operculodinium, particularly if they are folded and distorted. But it differs from Operculodinium by having an intercalary rather than a precingular archeopyle and by being dorsoventrally flattened. The processes of Barssidinium olymposa are different of these of Melitasphaeridium choanophorum in that they lack of indentations present on the aculeate process tips of M. choanophorum.
Remarks/Comments:
This species has not been observed in the Pliocene of The Bou Regreg Core samples.
Holotype: Warny et Wrenn, 1997: Plate IX, 3 and 4
Type locality: Bou Regreg S Core, Sale, Riffian Corridor, Morocco.
Stratum typicum: Messinian
Stratigraphic range: Miocene, samples B94 (162.5 m)-S 17 (18.54 m) ( Fig. 2).
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Warny et Wrenn, 1997, p. 299, 301]:
Diagnosis:
A spherical to ovoidal shaped species of Barssidinium bearing numerous nontabular processes primarily around the cyst margin.
Processes are flared distally. The distal termination of these processes is special in that each is usually a hemispherical bowl.
The operculum of the intercalary ( Type 2a) archeopyle is usually not free. The archeopyle is the only indication of paratabulation on the cyst.
Description:
Processes: Numerous nontabular processes with distal ends resembling the Olympic bowl. Process length varies from 6.8 to 11.9 µm with a mean of 8.6 µm. The ratio of the equatorial diameter of the central body and the length of processes is about 1/5 to 1/7. Processes are usually more abundant around the margin of the cyst.
Shape: Elliptical to rounded in plane view, and dorsoventrally compressed.
Phragma: The cysts are bound by an autophragm or two closely appressed wall layers. The surface is smooth to granulate.
Archeopyle: We assume that the archeopyle of B. olymposa is intercalary ( Type 2a) because the overall aspect of the cyst, and the large size and position (sitting low on the dorsal surface) of the archeopyle resemble those characteristics on other species of Barssidinium (Lentin et al., 1994). Its location is indicated on most specimens only by a slight opening of its sutures. On some specimens, the large operculum may resemble a precingular Type P archeopyle. The operculum is not free and may be adnate anteriorly.
Paratabulation: Paratabulation is indicated only by the Type 2a intercalary archeopyle.
Paracingulum: Not evident.
Parasulcus: Not discernible.
Dimensions:
Holotype: central body diameter 68.0 µm; length of process 5.1-8.5 µm. Mean (x) and extreme values for n= 11: central body diameter 47.6-(55.1)-68.0 µm; length of process 6.8-(8.6)-ll.9 µm.
Affinities/Comparison:
Barssidinium olymposa is of the same age and quite similar to Barssidinium soucouyantae (De Verteuil and Norris, 1992). However, its processes are totally different and the operculum often is not free. Specimens of S. olymposa may resemble some species of Operculodinium, particularly if they are folded and distorted. But it differs from Operculodinium by having an intercalary rather than a precingular archeopyle and by being dorsoventrally flattened. The processes of Barssidinium olymposa are different of these of Melitasphaeridium choanophorum in that they lack of indentations present on the aculeate process tips of M. choanophorum.
Remarks/Comments:
This species has not been observed in the Pliocene of The Bou Regreg Core samples.