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Oligosphaeridium perforatum ssp. colum
Oligosphaeridium perforatum ssp. colum Duxbury, 1983
Holotype: Duxbury, 1983, pl.8, fig.9
Locus typicus: Atherfield section, Isle of Wight
Stratum typicum: Aptian- Early Albian
Original diagnosis Duxbury, 1983, p.53:
A sub-species of Oligosphaeridium perforatum (Gocht, 1959) Davey and Williams, 1969 in which the distal process extremities are highly fenestrate.
Observed dimensions: Holotype - 84 x 110 Ám. Range: Main Body - 64 (55) 44 x 64 (55) 44 Ám. Processes - 20-52 Ám. Specimens measured - 15.
Remarks Duxbury, 1983, p.53:
The degree of distal process fenestration sets this sub-species apart from 0. perforatum (Gocht, 1959) Davey and Williams, 1969 ssp. perforatum Duxbury, which has distal process terminations similar in overall morphology to those of 0. perforatum ssp. colum, but possesses fewer perforations which may not be considered to form an overall fenestration (see Gocht, 1959). Oligosphaeridium dictyophorum (Cookson and Eisenack, 1958) Davey and Williams, 1979 is similar to 0. perforatum ssp. colum in possessing processes which are distally fenestrate. It differs, however, in having solid processes (atypical of the genus Oligosphaeridium) and in lacking the distinct angularity to the distal process extremes which is a major characteristic of 0. perforatum.
Holotype: Duxbury, 1983, pl.8, fig.9
Locus typicus: Atherfield section, Isle of Wight
Stratum typicum: Aptian- Early Albian
Original diagnosis Duxbury, 1983, p.53:
A sub-species of Oligosphaeridium perforatum (Gocht, 1959) Davey and Williams, 1969 in which the distal process extremities are highly fenestrate.
Observed dimensions: Holotype - 84 x 110 Ám. Range: Main Body - 64 (55) 44 x 64 (55) 44 Ám. Processes - 20-52 Ám. Specimens measured - 15.
Remarks Duxbury, 1983, p.53:
The degree of distal process fenestration sets this sub-species apart from 0. perforatum (Gocht, 1959) Davey and Williams, 1969 ssp. perforatum Duxbury, which has distal process terminations similar in overall morphology to those of 0. perforatum ssp. colum, but possesses fewer perforations which may not be considered to form an overall fenestration (see Gocht, 1959). Oligosphaeridium dictyophorum (Cookson and Eisenack, 1958) Davey and Williams, 1979 is similar to 0. perforatum ssp. colum in possessing processes which are distally fenestrate. It differs, however, in having solid processes (atypical of the genus Oligosphaeridium) and in lacking the distinct angularity to the distal process extremes which is a major characteristic of 0. perforatum.