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Oligosphaeridium complex ssp. complex
Oligosphaeridium complex ssp. complex
Autonym
Holotype: White, 1848, pl.4, fig.11 was lost
Neotype: Davey and Williams, 1966, pl.7, fig.1
Locus typicus (neotype): Fetcham Mill, Surrey, S England
Stratum typicum: Senonian (neotype: Cenomanian)
Original description: White 1842, p. 39: Xanthidium tubiferum complex
Emended diagnosis: Davey and Williams 1966, p. 71-72
Central body subspherical to ovoidal. Wall composed of thin endophragm and periphragm, the latter giving rise to processes. Processes simple or branched, cylindrical for most of their length, open and expanded distally with aculeate or secate margin. Reflected tabulation inferred 4", 6"", 5-6""", 1p, 1"""". Apical archaeopyle usually present having a zigzag margin. Processes in complete specimens not exceeding 18.
Dimensions: Range: diameter of central body 34-55µ, length of processes 22-43µ.
Description: Davey and Williams 1966, p. 72
In the specimens from the Cenomanian, the periphragm of the central body is smooth or very slightly granular. The processes are cylindrical for most of their length, with an expanded opening distally, the margin of which is developed into aculei and secae can be simple or branched, erect or patulate, orthogonal or even recurved. Where the processes meet the central body there is often a clearly marked ring indicating the point of divergence of the endophragm and periphragm. The wall of the processes is smooth or faintly fibrous; their length usually measures between the radius and the diameter of the central body.
The small number of processes and the apical archaeopyle, when present, enable one readily to determine the tabulation of O.complex as reflected by the position of the processes.
Affinities:
Davey and Williams, 1966, p. 73: Examples from the Speeton Clay (Barremian) of Yorkshire are very similar to the forms illustrated by Eisenack, 1958. The periphragm of the central body is often slightly granular and some of the processes are more deeply divided and show more variation than is usual in this species. 11 specimens were measured, the diameter of the central body being 35-62 µm and the length of the processes 13-47 µm.
Specimens from the London Clay (Ypresian) strongly resemble the Cenomanian forms, the processes perhaps being a little stouter. Diameter of central body 29-58 µm, length of processes 23-39 µm (6 specimans measured).
Autonym
Holotype: White, 1848, pl.4, fig.11 was lost
Neotype: Davey and Williams, 1966, pl.7, fig.1
Locus typicus (neotype): Fetcham Mill, Surrey, S England
Stratum typicum: Senonian (neotype: Cenomanian)
Original description: White 1842, p. 39: Xanthidium tubiferum complex
Emended diagnosis: Davey and Williams 1966, p. 71-72
Central body subspherical to ovoidal. Wall composed of thin endophragm and periphragm, the latter giving rise to processes. Processes simple or branched, cylindrical for most of their length, open and expanded distally with aculeate or secate margin. Reflected tabulation inferred 4", 6"", 5-6""", 1p, 1"""". Apical archaeopyle usually present having a zigzag margin. Processes in complete specimens not exceeding 18.
Dimensions: Range: diameter of central body 34-55µ, length of processes 22-43µ.
Description: Davey and Williams 1966, p. 72
In the specimens from the Cenomanian, the periphragm of the central body is smooth or very slightly granular. The processes are cylindrical for most of their length, with an expanded opening distally, the margin of which is developed into aculei and secae can be simple or branched, erect or patulate, orthogonal or even recurved. Where the processes meet the central body there is often a clearly marked ring indicating the point of divergence of the endophragm and periphragm. The wall of the processes is smooth or faintly fibrous; their length usually measures between the radius and the diameter of the central body.
The small number of processes and the apical archaeopyle, when present, enable one readily to determine the tabulation of O.complex as reflected by the position of the processes.
Affinities:
Davey and Williams, 1966, p. 73: Examples from the Speeton Clay (Barremian) of Yorkshire are very similar to the forms illustrated by Eisenack, 1958. The periphragm of the central body is often slightly granular and some of the processes are more deeply divided and show more variation than is usual in this species. 11 specimens were measured, the diameter of the central body being 35-62 µm and the length of the processes 13-47 µm.
Specimens from the London Clay (Ypresian) strongly resemble the Cenomanian forms, the processes perhaps being a little stouter. Diameter of central body 29-58 µm, length of processes 23-39 µm (6 specimans measured).