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Phthanoperidinium ormenlangei
Phthanoperidinium ormenlangei, Vieira, M. et al., 2018, p. 191
Holotype: Vieira, M. et al., 2018, Plate 5, figure 9
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:
This peridinoid cyst possesses a subpolygonal shape, with one short, small apical horn and with or without two antapical lobes. The cyst is composed of periphragm and endophragm very closely adpressed together, not clearly differentiated except beneath horns, with one short, blunt, distinct apical horn, and with two reduced antapical lobes or without antapical lobes. Both walls are very thin forming a relatively
high and smooth parasutural crest that is distally smooth to punctate, occasionally finely denticulate.
Paratabulation: distinct, expressed by the parasutural crest.
The periphragm is thin, smooth or ornamented with undulating crests which delineate a paratabulation and partial thickening which defines
the paracingulum. The crest is fairly prominent (height up to 2 µm), whereas the periphragm is often highly folded and occasionally bears verrucae up to 2 µm in height and width.
Archeopyle: Intercalary, is usually present and the operculum is free.
Dimensions:
Holotype: pericyst length 43 µm, width 39 µm; length of apical horn 5.5 µm.
20 specimens measured: Pericyst length 38 (43) 57 µm, width 33 (38) 48 µm – height of septa up to 2.5 µm – apical horn length less
than 5.5 µm.
Remarks:
Islam (1982) emended the diagnosis of the genus and noted that the recorded stratigraphic ranges of most of the species are Eocene to Oligocene in age. However, Phthanoperidinium paleocenicum Lucas-Clark (2006) was recorded from the Early Paleocene of South Carolina, so this new species of Phthanoperidinium is not the first recovered from Danian strata.
Affinities/Comparison:
This species differs from others of the genus by its distinct but smooth parasutural crests. Phthanoperidinium levimurum Bujak (1980) has crests that are thin and smooth, but may be finely denticulate in the paracingulum region. Phthanoperidinium alectrolophorum Eaton (1976) has crests that are capped with a row of low spines. Phthanoperidinium cornutum Heilmann-Clausen & Van Simaeys (2005) is noted for its long and sharp apical horn.
Holotype: Vieira, M. et al., 2018, Plate 5, figure 9
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:
This peridinoid cyst possesses a subpolygonal shape, with one short, small apical horn and with or without two antapical lobes. The cyst is composed of periphragm and endophragm very closely adpressed together, not clearly differentiated except beneath horns, with one short, blunt, distinct apical horn, and with two reduced antapical lobes or without antapical lobes. Both walls are very thin forming a relatively
high and smooth parasutural crest that is distally smooth to punctate, occasionally finely denticulate.
Paratabulation: distinct, expressed by the parasutural crest.
The periphragm is thin, smooth or ornamented with undulating crests which delineate a paratabulation and partial thickening which defines
the paracingulum. The crest is fairly prominent (height up to 2 µm), whereas the periphragm is often highly folded and occasionally bears verrucae up to 2 µm in height and width.
Archeopyle: Intercalary, is usually present and the operculum is free.
Dimensions:
Holotype: pericyst length 43 µm, width 39 µm; length of apical horn 5.5 µm.
20 specimens measured: Pericyst length 38 (43) 57 µm, width 33 (38) 48 µm – height of septa up to 2.5 µm – apical horn length less
than 5.5 µm.
Remarks:
Islam (1982) emended the diagnosis of the genus and noted that the recorded stratigraphic ranges of most of the species are Eocene to Oligocene in age. However, Phthanoperidinium paleocenicum Lucas-Clark (2006) was recorded from the Early Paleocene of South Carolina, so this new species of Phthanoperidinium is not the first recovered from Danian strata.
Affinities/Comparison:
This species differs from others of the genus by its distinct but smooth parasutural crests. Phthanoperidinium levimurum Bujak (1980) has crests that are thin and smooth, but may be finely denticulate in the paracingulum region. Phthanoperidinium alectrolophorum Eaton (1976) has crests that are capped with a row of low spines. Phthanoperidinium cornutum Heilmann-Clausen & Van Simaeys (2005) is noted for its long and sharp apical horn.