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Suessia scabrata
Suessia? scabrata sp. nov., Mantle et al. 2020, p. 33
Holotype: Mantle et al. 2020, Plate II, 4
Type locality: Northern Carnarvon Basin
Local stratigraphical range: Late Triassic (uppermost Carnian–Rhaetian)
Original description: Mantle et al. 2020:
Description:
Small, acavate, proximate, subspherical dinoflagellate cysts with approximately equant epicysts and hypocysts.
Wall: the autophragm is microgranulate to scabrate and commonly folded.
Tabulation: suessioid tabulation is only partially expressed around the archaeopyle margins and the number of latitudinal plate series is not known (though it appears to have at least six plate series and likely more)
Archaeopyle: formed by the progressive loss of the apical and intercalary plates (probably involving the anterior intercalary and postapical plates)
Operculum: compound. A small, subcircular, red-brown accumulation body (4–6 μm) is occasionally present close to the cingulum.
Dimensions:
Overall length (excluding apical plates) 27 μm (29 μm) 30 μm; maximum width 26 μm (32 μm) 36 μm
10 measured specimens
Remarks:
Morbey (1975) and Below (1987) both recorded a thin outer wall layer on well preserved specimens of Suessia swabiana. Thus, the single wall layer observed herein for Suessia? scabrata sp. nov. may represent closely appressed periphragm and endophragm, or the former is not preserved in the material studied herein. The suessioid tabulation formula is only expressed faintly, therefore a questionable generic assignment is made. However, the lack of spinose elements, and the compound rather than simple operculum, is strongly suggestive of Suessia rather than Wanneria.
Affinities/Comparison:
Suessia? scabrata sp. nov. is, on average, substantially smaller than Suessia disintegra sp. nov., has more prominent surface ornament and typically lacks any sutural features other than the archaeopyle margin. It could possibly be considered an extreme end member of Suessia disintegra sp. nov., but as it is considerably different to the larger or more strongly tabulate forms of that taxon it is considered separate herein.
Holotype: Mantle et al. 2020, Plate II, 4
Type locality: Northern Carnarvon Basin
Local stratigraphical range: Late Triassic (uppermost Carnian–Rhaetian)
Original description: Mantle et al. 2020:
Description:
Small, acavate, proximate, subspherical dinoflagellate cysts with approximately equant epicysts and hypocysts.
Wall: the autophragm is microgranulate to scabrate and commonly folded.
Tabulation: suessioid tabulation is only partially expressed around the archaeopyle margins and the number of latitudinal plate series is not known (though it appears to have at least six plate series and likely more)
Archaeopyle: formed by the progressive loss of the apical and intercalary plates (probably involving the anterior intercalary and postapical plates)
Operculum: compound. A small, subcircular, red-brown accumulation body (4–6 μm) is occasionally present close to the cingulum.
Dimensions:
Overall length (excluding apical plates) 27 μm (29 μm) 30 μm; maximum width 26 μm (32 μm) 36 μm
10 measured specimens
Remarks:
Morbey (1975) and Below (1987) both recorded a thin outer wall layer on well preserved specimens of Suessia swabiana. Thus, the single wall layer observed herein for Suessia? scabrata sp. nov. may represent closely appressed periphragm and endophragm, or the former is not preserved in the material studied herein. The suessioid tabulation formula is only expressed faintly, therefore a questionable generic assignment is made. However, the lack of spinose elements, and the compound rather than simple operculum, is strongly suggestive of Suessia rather than Wanneria.
Affinities/Comparison:
Suessia? scabrata sp. nov. is, on average, substantially smaller than Suessia disintegra sp. nov., has more prominent surface ornament and typically lacks any sutural features other than the archaeopyle margin. It could possibly be considered an extreme end member of Suessia disintegra sp. nov., but as it is considerably different to the larger or more strongly tabulate forms of that taxon it is considered separate herein.