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Oligosphaeridium porosum
Oligosphaeridium porosum Lentin and Williams, 1981, nom. subst. pro Oligosphaeridium perforatum Jain, 1977, non Oligosphaeridium perforatum (Gocht, 1959) Davey and Williams, 1969
Originally Oligosphaeridium perforatum Jain, 1977b (name illegitimate), subsequently (and now) Oligosphaeridium porosum.
Holotype: Jain 1977b Pl. 1, fig. 5
Locus typicus: Kallakkudi Limestone quarry II, Dalmiapuram, South India.
Stratum typicum:Grey Shale member, Dalmiapuram Formation; Early Albian.
Age: Early Albian
Original diagnosis: Jain 1977b: p. 181: Oligosphaeridium perforatum
Cyst subspherical to elongate, double walled, periphragm smooth to granular, gives rise to 18 processes, 4 apical mostly not seen, separated with operculum), 6 precingular, 6 post cingular, one antapical and one posterior intercalary. Process stem short or absent. In processes with stem distal widening starts half way, in stemless it starts just from the surface. Processes thick at the proximal contact with periphragm giving rise to a basal ring like structure, distally perforate branched, distal rim spinose and discontinuous; antapical process mostly stemless. Archaeopyle apical.
Measurements Holotype Range
Diameter of cyst 70µm 30-70µm
Length of process 26µm 18-30µm
Comparison: Jain 1977b: p. 181
O. perforatum sp. nov. compares best with O. pulcherrimum in having distally perforate processes. Former differs in having very short processes with and without stem. O. poculum sp. nov. differs in having only vase or cup shaped stemless processes.
Originally Oligosphaeridium perforatum Jain, 1977b (name illegitimate), subsequently (and now) Oligosphaeridium porosum.
Holotype: Jain 1977b Pl. 1, fig. 5
Locus typicus: Kallakkudi Limestone quarry II, Dalmiapuram, South India.
Stratum typicum:Grey Shale member, Dalmiapuram Formation; Early Albian.
Age: Early Albian
Original diagnosis: Jain 1977b: p. 181: Oligosphaeridium perforatum
Cyst subspherical to elongate, double walled, periphragm smooth to granular, gives rise to 18 processes, 4 apical mostly not seen, separated with operculum), 6 precingular, 6 post cingular, one antapical and one posterior intercalary. Process stem short or absent. In processes with stem distal widening starts half way, in stemless it starts just from the surface. Processes thick at the proximal contact with periphragm giving rise to a basal ring like structure, distally perforate branched, distal rim spinose and discontinuous; antapical process mostly stemless. Archaeopyle apical.
Measurements Holotype Range
Diameter of cyst 70µm 30-70µm
Length of process 26µm 18-30µm
Comparison: Jain 1977b: p. 181
O. perforatum sp. nov. compares best with O. pulcherrimum in having distally perforate processes. Former differs in having very short processes with and without stem. O. poculum sp. nov. differs in having only vase or cup shaped stemless processes.