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Areoligera constricta
Areoligera constricta, Vieira, M. et al., 2018, p. 185
Holotype: Vieira, M. et al., 2018, Plate 2, figures 1–2
Type locality: southern part of the Ormen Lange field (Norway) over the Danian-aged reservoir
Local stratigraphical range: Danian (Early Paleocene)
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Original description: [Vieira, M. et al., 2018]:
Diagnosis:
Proximochorate to chorate cysts, cyst body usually dorsoventrally flattened with circular to sub-circular outline with smooth, punctate to finely granulate surface. Ventral and dorsal surfaces bear process membranes with lobate or undulating distal margins which form curved troughs with pointed crests surrounded by acuminate spines.
Processes: intratabular, restricted to the peripheral zone of the cyst body. These processes proximally can be non-fenestrate membranes with the processes arising from the distal margin of the cyst body, and can be connected along their length by a membrane. The are usually organised into arcuate, soleate or annulate complexes bearing numerous spines projecting from the membrane; distally these slender processes can be acuminate or bifid; in one individual the processes of adjacent complexes are united distally by trabeculae.
Archeopyle: apical, tetratabular
Dimensions:
Holotype: cyst body length 48 µm, width 51 µm (without operculum); length 74 µm, width 76.5 µm (with processes), length of processes 24 µm.
20 specimens measured: Cyst body length 46 (53) 59 µm, width 43 (52.6) 70 µm (without operculum); cyst body length 62 (75.5) 86 µm, width 65 (77) 86 µm (with processes), length of processes 23 (27) 29 µm.
Remarks:
This species was first identified in several Ormen Lange wells from Danian-aged sediments. The species has also been observed from Danian strata across the North Sea and Norwegian Sea Basins by RPS Ichron Ltd. consultants, but has never been formally published.
Affinities/Comparison:
The presence of distinctive membranes, which connect distally along their length with adjacent processes forming a
curved trough, distinguishes this species from all described species of Areoligera.
Holotype: Vieira, M. et al., 2018, Plate 2, figures 1–2
Type locality: southern part of the Ormen Lange field (Norway) over the Danian-aged reservoir
Local stratigraphical range: Danian (Early Paleocene)
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Vieira, M. et al., 2018]:
Diagnosis:
Proximochorate to chorate cysts, cyst body usually dorsoventrally flattened with circular to sub-circular outline with smooth, punctate to finely granulate surface. Ventral and dorsal surfaces bear process membranes with lobate or undulating distal margins which form curved troughs with pointed crests surrounded by acuminate spines.
Processes: intratabular, restricted to the peripheral zone of the cyst body. These processes proximally can be non-fenestrate membranes with the processes arising from the distal margin of the cyst body, and can be connected along their length by a membrane. The are usually organised into arcuate, soleate or annulate complexes bearing numerous spines projecting from the membrane; distally these slender processes can be acuminate or bifid; in one individual the processes of adjacent complexes are united distally by trabeculae.
Archeopyle: apical, tetratabular
Dimensions:
Holotype: cyst body length 48 µm, width 51 µm (without operculum); length 74 µm, width 76.5 µm (with processes), length of processes 24 µm.
20 specimens measured: Cyst body length 46 (53) 59 µm, width 43 (52.6) 70 µm (without operculum); cyst body length 62 (75.5) 86 µm, width 65 (77) 86 µm (with processes), length of processes 23 (27) 29 µm.
Remarks:
This species was first identified in several Ormen Lange wells from Danian-aged sediments. The species has also been observed from Danian strata across the North Sea and Norwegian Sea Basins by RPS Ichron Ltd. consultants, but has never been formally published.
Affinities/Comparison:
The presence of distinctive membranes, which connect distally along their length with adjacent processes forming a
curved trough, distinguishes this species from all described species of Areoligera.