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Operculodinium runtatum
Operculodinium runtatum, Vieira, M. et al., 2018, p. 189, 191
Holotype: Vieira, M. et al., 2018, Plate 5, figure 1
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 skolochorate cyst with spherical to subspherical shape and consisting of two layers, with the periphragm and autophragm adpressed between processes. The cyst wall is relatively thick (up to 2.5 µm), punctate to finely granulate.
Paratabulation: not clear using an optical microscope, and only visible by the loss of the archeopyle.
Processes: non-tabular, short, varying in length between 4 and 8 µm, truncated, seldom straight, cylindrical with broad bases randomly distributed across the central body. These processes are usually uniform on a single specimen, with occasional processes showing to be
curved, smooth and with distal extremities that are minutely furcate.
Archeopyle: precingular, free operculum
Dimensions:
Holotype: cyst diameter 53 µm, width 48 µm.
20 specimens measured: Cyst diameter 40 (49) 68 µm, length of processes 4 (5.5) 8 µm
Affinities/Comparison:
This species often possesses truncated processes, a thick wall and robust central body, which allow this species to be differentiated from others within the genus. Operculodinium nanaconulum Islam (1983) differs from the present new species in having conical processes with pointed tips.
Holotype: Vieira, M. et al., 2018, Plate 5, figure 1
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 skolochorate cyst with spherical to subspherical shape and consisting of two layers, with the periphragm and autophragm adpressed between processes. The cyst wall is relatively thick (up to 2.5 µm), punctate to finely granulate.
Paratabulation: not clear using an optical microscope, and only visible by the loss of the archeopyle.
Processes: non-tabular, short, varying in length between 4 and 8 µm, truncated, seldom straight, cylindrical with broad bases randomly distributed across the central body. These processes are usually uniform on a single specimen, with occasional processes showing to be
curved, smooth and with distal extremities that are minutely furcate.
Archeopyle: precingular, free operculum
Dimensions:
Holotype: cyst diameter 53 µm, width 48 µm.
20 specimens measured: Cyst diameter 40 (49) 68 µm, length of processes 4 (5.5) 8 µm
Affinities/Comparison:
This species often possesses truncated processes, a thick wall and robust central body, which allow this species to be differentiated from others within the genus. Operculodinium nanaconulum Islam (1983) differs from the present new species in having conical processes with pointed tips.