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Saturnodinium pansum

Saturnodinium pansum (Stover, 1977) Brinkhuis et al.,1992

Originally Thalassiphora?, subsequently (and now) Saturnodinium.
Holotype: Stover, 1977, pl.2, figs.34-36
Locus typicus: Corehole 5/5B, Blake Plateau, Western N Atlantic
Stratum typicum: Middle Oligocene

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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.

Saturnodinium pansum (Stover, 1977) Brinkhuis et al., 1992. According to Brinkhuis et al. (1992), Saturnodinium pansum is a camocavate cyst characterized by a non-perforate periphragm and a paracingulum adorned by linear groupings of short spines, which may be single or in epicystal-hypocystal pairs. Width of linear groupings of denticles or spines may be single or in apical-antapical pairs (one above the other), and groups on the dorsal surface are more commonly paired than others. Width of linear groups is 8-30 µm, and the number of projections in each group varies from 2 to 10 and is usually 5. A large midventral paracingular pore-like opening occurs in the periphragm. Size: overall in apical-antapical view 64 by 66 to 82 by 84 µm, endocyst diameter 38-50 µm.
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Original description: Stover, 1977, p. 78: Thalassiphora? pansa
Cysts are cavate, compressed equatorially, and the outline of the pericyst is subcircular, generally with shallow concavities. Endocyst is subspherical, but its shape is almost always modified by folding. Endophragm is thin and smooth; periphragm is also thin, smooth or faintly ornamented and may have faint parasutural lines. Periphragm appressed to endophragm dorsally and separated elsewhere with the resulting pericoel being exceptionally wide ventrally. Archeopyle is precingular, type P, formed by release of paraplate 3'' only, and the operculumis free. Paratabulation indicated mainly by archeopyle and paracingulum; parasutural features are discontinuous and occur inconsistently. Paracingulum indicated marginally by 5 to 10 linear groups of denticles or short spines separated by generally shallow concavities. Linear groups may be single or inapical-antapical pairs (one above the other), and groups on the dorsal surface are more commonly paired than the others. Width of linear groups is 8 to 30 µm, and the number of projections in each group varies from 2 to 10 and is usually 5. A large midventral paracingular pore-like opening occurs in the periphragm. Parasulcus is not expressed. Overall size in apical-antapical view is 64 by 66 µm to 82 by 84 µm; endocystdiameter 38 to 50 µm.

Affinities: Stover, 1977, p. 78-79: Thalassiphora? pansa
The unique characteristics of Thalassiphora? pansa are its preferred apical-antapical flattening, the presence of paracingular linear groups of denticles or short spines on the periphragm and the paracingular pore-like feature in the midventral area. Among species of Thalassiphora, T. delicata Williams and Downie in Davey et al., 1966 emend. Eaton, 1976 appearsmost similar to T. ? pansa; it differs from T. ? pansa by having low parasutural ridges, a much larger ventral opening that is not confined to the paracingulum and by lacking the groups of denticles or short spines along the paracingulum. The new species is placed in Thalassiphora with reservation because of its apical-antapical flattening - a condition not associated with the current concept of the genus.
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Remarks: Brinkhuis et al., 1992, p. 246: Saturnodinium pansum comb. nov.
Saturnodinium pansum comb. nov. is a camocavate species characterized by a non-perforate periphragm and a paracingulum adorned by linear groupings of short spines, which may be single or in epicystal-hypocystal pairs. Stover (1977) assigned this species questionably to Thalassiphora Eisenack & Gocht 1960 emend. Benedek & Gocht 1981 because equatorial compression is a feature not associated with that genus. Saturnodinium pansum comb. nov. has not been recorded from samples of the present study. The specimen illustrated by Powell (1986a) as Thalassiphora sp. cf. Thalassiphora? pansa is similar in that it is camocavate and exhibits polar compression; it differs however, by having continuous rims to the paracingulum which lack groups of short spines. Allocation to the genus Gelatia Bujak 1984 is not feasible due to the lack of an epicystal opening on the pericyst; it is most likely
an, as yet, undescribed species of Saturnodinium.

Basionym. Thalassiphora? pansa Stover 1977, p. 78.

Thalassiphora? pansa Stover 1977, p. 78; pl. 2, figs. 32-38.
non Thalassiphora sp. cf. Thalassiphora? pansa Stover;Powell, 1986a, pl. 7, fig. 6 [= ? Saturnodinium sp. indet.]
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