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Cordosphaeridium fibrospinosum
Cordosphaeridium fibrospinosum, Davey and Williams, 1966
Originally (and now) Cordosphaeridium, subsequently Emmetrocysta?, thirdly Tityrosphaeridium?.
Sarjeant, 1981, provisionally transferred this species to Emmetrocysta Stover, 1975. Lentin and Williams, 1985, retained it in Cordosphaeridium. Jain and Garg, 1986, questionably transferred this species to Tityrosphaeridium Sarjeant, 1981. Lentin and Williams, 1989, retained it in Cordosphaeridium.
Taxonomic junior synonyms: Cordosphaeridium exilimurum and Achomosphaera (subsequently Cordosphaeridium) valianta, both according to Fensome et al. (2009, p.23).
Holotype: Davey and Williams 1966, p.86, pl.5, fig.5; Bujak et al., 1980, pl.7, figs.3,6
Locus typicus: Enborne, Berkshire, England
Occurrence: Paleocene- ?Late Eocene.
Stratum typicum: Early Eocene
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Original description: [Davey and Williams, 1966, p. 86]:
Diagnosis:
Ovoidal central body with wall up to 5 µm thick, composed of smooth endophragm and fibrous periphragm.
Processes fibrous, often very broad and ovoidal in cross-section, walls perforate. Processes open distally, with entire or undulose margin. One process per plate reflecting a tabulation typical of genus.
Archaeopyle apical haplotabular.
Description:
This species is characterized by fibrous, often perforate, processes which can be latispinous. The perforations show no regularity in arrangement and tend to be elongate.
The cross-section of the processes is ovoidal or rarely cylindrical and then only in the narrower processes. The lengths of the processes vary considerably in different specimens but rarely exceed half the diameter of the central body. It should be noted that in the broader processes, the width often exceeds the length.
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Supplemental description:
Davey, 1969, p. 36:
Revised diagnosis:
Central body ovoidal with wall up to 0.5 µm thick, composed of smooth endophragm and fibro-pitted periphragm.
Processes fibrous, one per plate-area, often very broad and ovoidal in cross-section; walls perforate. Processes open distally with entire or undulose margin.
Archaeopyle typically present.
Description:
This species is characterised by a thin-walled fibro-pitted central body and one process per plate-area. The width of the processes is variable and sometimes be equal to the process length. Their length on each specimen is more or less constant and approximately equal to one-third of the central body diameter. The processes are typically tubiform but occasionally they do subdivide distally. The walls of the processes are extremely fine and fibrous, and usually appear to be fenestrate or perforate. The apical and antapical processes appear to be of equal size to the remaining processes.
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Gocht, 1969, p.43, 44: (Translation: Geological Survey of Canada):
Description and remarks:
This species is characterized by the broad, truncate cylinders of the larger processes of the pre- and post cingular series and at the poles. They rise, often without distinct basal boundaries, from the fibrous external membrane and are evidently hollow. Distally they may end without widening distinctly, or they may also be distinctly widened or fanned out. The cingular series frequently has very flattened processes, while in the ventral region narrow appendages are dominant. One specimen has a cingular fringe. Unfortunately, most specimens are inadequately preserved. The attempt to ascertain and interpret the arrangement of processes is based only on a few individuals: 2-3', 6'', 6c, 5''', 1''''; 2-3 p.
This species varies greatly. In deeper samples, the large processes are usually wider than high; such forms are reported also in Davey and Williams.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999
Cordosphaeridium fibrospinosum Davey and Williams, 1966b, emend. Davey, 1969b has processes of variable width, the broadest being on the pre- and postcingular plates and at the antapex. Processes strongly fibrous, often look perforate.
Size central body 59-72 µm, process length up to 39 µm, width up to 26 µm.
Originally (and now) Cordosphaeridium, subsequently Emmetrocysta?, thirdly Tityrosphaeridium?.
Sarjeant, 1981, provisionally transferred this species to Emmetrocysta Stover, 1975. Lentin and Williams, 1985, retained it in Cordosphaeridium. Jain and Garg, 1986, questionably transferred this species to Tityrosphaeridium Sarjeant, 1981. Lentin and Williams, 1989, retained it in Cordosphaeridium.
Taxonomic junior synonyms: Cordosphaeridium exilimurum and Achomosphaera (subsequently Cordosphaeridium) valianta, both according to Fensome et al. (2009, p.23).
Holotype: Davey and Williams 1966, p.86, pl.5, fig.5; Bujak et al., 1980, pl.7, figs.3,6
Locus typicus: Enborne, Berkshire, England
Occurrence: Paleocene- ?Late Eocene.
Stratum typicum: Early Eocene
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Original description: [Davey and Williams, 1966, p. 86]:
Diagnosis:
Ovoidal central body with wall up to 5 µm thick, composed of smooth endophragm and fibrous periphragm.
Processes fibrous, often very broad and ovoidal in cross-section, walls perforate. Processes open distally, with entire or undulose margin. One process per plate reflecting a tabulation typical of genus.
Archaeopyle apical haplotabular.
Description:
This species is characterized by fibrous, often perforate, processes which can be latispinous. The perforations show no regularity in arrangement and tend to be elongate.
The cross-section of the processes is ovoidal or rarely cylindrical and then only in the narrower processes. The lengths of the processes vary considerably in different specimens but rarely exceed half the diameter of the central body. It should be noted that in the broader processes, the width often exceeds the length.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Supplemental description:
Davey, 1969, p. 36:
Revised diagnosis:
Central body ovoidal with wall up to 0.5 µm thick, composed of smooth endophragm and fibro-pitted periphragm.
Processes fibrous, one per plate-area, often very broad and ovoidal in cross-section; walls perforate. Processes open distally with entire or undulose margin.
Archaeopyle typically present.
Description:
This species is characterised by a thin-walled fibro-pitted central body and one process per plate-area. The width of the processes is variable and sometimes be equal to the process length. Their length on each specimen is more or less constant and approximately equal to one-third of the central body diameter. The processes are typically tubiform but occasionally they do subdivide distally. The walls of the processes are extremely fine and fibrous, and usually appear to be fenestrate or perforate. The apical and antapical processes appear to be of equal size to the remaining processes.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Gocht, 1969, p.43, 44: (Translation: Geological Survey of Canada):
Description and remarks:
This species is characterized by the broad, truncate cylinders of the larger processes of the pre- and post cingular series and at the poles. They rise, often without distinct basal boundaries, from the fibrous external membrane and are evidently hollow. Distally they may end without widening distinctly, or they may also be distinctly widened or fanned out. The cingular series frequently has very flattened processes, while in the ventral region narrow appendages are dominant. One specimen has a cingular fringe. Unfortunately, most specimens are inadequately preserved. The attempt to ascertain and interpret the arrangement of processes is based only on a few individuals: 2-3', 6'', 6c, 5''', 1''''; 2-3 p.
This species varies greatly. In deeper samples, the large processes are usually wider than high; such forms are reported also in Davey and Williams.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999
Cordosphaeridium fibrospinosum Davey and Williams, 1966b, emend. Davey, 1969b has processes of variable width, the broadest being on the pre- and postcingular plates and at the antapex. Processes strongly fibrous, often look perforate.
Size central body 59-72 µm, process length up to 39 µm, width up to 26 µm.