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Stephodinium dianneae
Stephodinium dianneae Morgan, 1980
Tax. sr. synonym of Stephodinium daveyi Below, 1982, according to Lister and Batten, 1988.
Holotype: Morgan, 1980, pl.28, fig.1-4
Locus typicus: Santos Oodnadatta, Australia
Stratum typicum: Aptian-Early Albian
Original description: Morgan, 1980, p. 32
Cyst double walled, endophragm ambitus subcircular, periphragm ambitus rhombic; endophragm subspherical, 0.5-1.0 µm thick; periphragm closely appressed to endophragm except at Ihe cingulum and apex; apical horn hollow, conical, about 15 µm in base diameter and 10 µm high; paracingulum an inflated pericoel 5-12 µm high and 5-7 µm broad, strongly offset at the sulcus; periphragm bears non-tabular short solid spines 3-5 µm long, and parasutural ridges 0.5-1.0 µm high which may bear a few spines reflecting gonyaulacean tabulation; inflated cingulum bears paired parasutural ridges along the top spines absent from inflated apical horn and paracingulum except beneath the archeypyle; archeopyle precingular, periarcheopyle including the adjacent portion of the inflated cingulum; operculum free.
Affinities:
Morgan, 1980, p. 32: S. dianneae may be removed to a new genus in the future, as it differs from all descrihed species of Stephodinium by having dense intratabular spines, a narrower inflated cingulum, and by lacking high parasulcal crests. Stephodinium spiniferum Cookson and Eisenack 1965 has a few parasutural spines along the cingulum parasutures only. S. dianneae differs from spinose species of Gonyaulacysta by having an inflated paracingulum.
Tax. sr. synonym of Stephodinium daveyi Below, 1982, according to Lister and Batten, 1988.
Holotype: Morgan, 1980, pl.28, fig.1-4
Locus typicus: Santos Oodnadatta, Australia
Stratum typicum: Aptian-Early Albian
Original description: Morgan, 1980, p. 32
Cyst double walled, endophragm ambitus subcircular, periphragm ambitus rhombic; endophragm subspherical, 0.5-1.0 µm thick; periphragm closely appressed to endophragm except at Ihe cingulum and apex; apical horn hollow, conical, about 15 µm in base diameter and 10 µm high; paracingulum an inflated pericoel 5-12 µm high and 5-7 µm broad, strongly offset at the sulcus; periphragm bears non-tabular short solid spines 3-5 µm long, and parasutural ridges 0.5-1.0 µm high which may bear a few spines reflecting gonyaulacean tabulation; inflated cingulum bears paired parasutural ridges along the top spines absent from inflated apical horn and paracingulum except beneath the archeypyle; archeopyle precingular, periarcheopyle including the adjacent portion of the inflated cingulum; operculum free.
Affinities:
Morgan, 1980, p. 32: S. dianneae may be removed to a new genus in the future, as it differs from all descrihed species of Stephodinium by having dense intratabular spines, a narrower inflated cingulum, and by lacking high parasulcal crests. Stephodinium spiniferum Cookson and Eisenack 1965 has a few parasutural spines along the cingulum parasutures only. S. dianneae differs from spinose species of Gonyaulacysta by having an inflated paracingulum.