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Tubotuberella owensii
From Fensome et al., 2019:
Tubotuberella owensii Poulsen, 1996, p.78–79, pl.34, figs.1–9.
Holotype: Poulsen, 1996, pl.34, figs.4–5.
Age: Oxfordian.
Paratype. Pl. 34, Figs. 1-3, 6-7; DGU catalogue no.: 1991-NEP-2,3, sample details as for the holotype.
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Poulsen 1996, p. 78-79
Tubotuberella owensii sp. nov., Pl. 34, Figs. 1-9
Diagnosis. A round, inverted tear-drop shaped proximate cyst which is stoibocavate or sometimes only hypocavate. The apical horn is small when present. The hypocyst has a short conical protrusion which is open distally. The endocyst is separated from the pericyst antapically, elsewhere closely appressed. In specimens with an apical horn, it is formed by the ectophragm. The periphragm is faintly ornamented with nontabular granules, and has low parasutural ridges. The endophragm is smooth. The paratabulation is gonyaulacoid. The archeopyle is precingular, type P3""a. The operculum is attached along the cingulum. The parasulcus is broad, no paratabulation is indicated within the parasulcal area.
Description: A round, inverted tear-drop shaped species of Tubotuberella with a short, broad antapical protrusion. A very small apical horn is generally present. The cyst has two wall layers, which are in contact except in the apical horn and in the antapical protrusion, resulting in a stoibocavate (having wall layers that are conspicuously separated in the anterior part of the cyst and at or near the base of the horn in the posterior proportion of the cyst, Sarjeant, 1982a) or, when the apical horn is reduced, hypocavate cyst. The periphragm has small, nontabular granules and bears low parasutural ridges. The periphragm has an opisthopyle at the antapex. The endophragm is smooth. The paracingulum is indicated by low parasutural ridges. The paratabulation formula is 3-4", 6", ?c, 5-6"", 1p, 1"", 5s. The archeopyle is precingular with an attached operculum along the paracingulum, type P3""a. The paracingulum and the parasulcus are expressed as areas between parasutural ridges. The parasutures are seen only rarely within the paracingulum, and never within the parasulcus. The size of this species is small.
Dimensions:
The apical horn is 0-3 µm long, the antapical protrusion is about 10-12 µm long. 30 specimens measured.
Holotype: length 48 µm, width 35 µm, length of endocyst 38 µm.
Paratype 1991-NEP-2: length 62 µm, width 48 µm, length of endocyst 45 µm. Paratype 1991-NEP-3: length 57 µm, width 38 µm, length of endocyst 41 µm.
Overall cyst length (minimum-mean-maximum): 43 µm - 56 µm - 65 µm
Overall cyst width (minimum-mean-maximum): 37 µm - 43 µm - 51 µm.
Comparison: Tubotuberella owensii resembles most Tubotuberella egemenii (Gitmez 1970) Stover and Evitt 1978, from which it differs by being slightly smaller and stoibocavate or hypocavate.
Recorded occurrences: Tubotuberella owensii is found in the Late Oxfordian of the Fjerritslev-2 borehole (1266-68 m) and in the Oxfordian of the Harald Field in the Danish part of the Central Trough (Lulu-1 borehole at 11650 ft., West Lulu-1 at 11600 ft., West Lulu-2 at 12300 ft. See Nielsen and Japsen, 1991 for location of the two boreholes.
Tubotuberella owensii Poulsen, 1996, p.78–79, pl.34, figs.1–9.
Holotype: Poulsen, 1996, pl.34, figs.4–5.
Age: Oxfordian.
Paratype. Pl. 34, Figs. 1-3, 6-7; DGU catalogue no.: 1991-NEP-2,3, sample details as for the holotype.
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Poulsen 1996, p. 78-79
Tubotuberella owensii sp. nov., Pl. 34, Figs. 1-9
Diagnosis. A round, inverted tear-drop shaped proximate cyst which is stoibocavate or sometimes only hypocavate. The apical horn is small when present. The hypocyst has a short conical protrusion which is open distally. The endocyst is separated from the pericyst antapically, elsewhere closely appressed. In specimens with an apical horn, it is formed by the ectophragm. The periphragm is faintly ornamented with nontabular granules, and has low parasutural ridges. The endophragm is smooth. The paratabulation is gonyaulacoid. The archeopyle is precingular, type P3""a. The operculum is attached along the cingulum. The parasulcus is broad, no paratabulation is indicated within the parasulcal area.
Description: A round, inverted tear-drop shaped species of Tubotuberella with a short, broad antapical protrusion. A very small apical horn is generally present. The cyst has two wall layers, which are in contact except in the apical horn and in the antapical protrusion, resulting in a stoibocavate (having wall layers that are conspicuously separated in the anterior part of the cyst and at or near the base of the horn in the posterior proportion of the cyst, Sarjeant, 1982a) or, when the apical horn is reduced, hypocavate cyst. The periphragm has small, nontabular granules and bears low parasutural ridges. The periphragm has an opisthopyle at the antapex. The endophragm is smooth. The paracingulum is indicated by low parasutural ridges. The paratabulation formula is 3-4", 6", ?c, 5-6"", 1p, 1"", 5s. The archeopyle is precingular with an attached operculum along the paracingulum, type P3""a. The paracingulum and the parasulcus are expressed as areas between parasutural ridges. The parasutures are seen only rarely within the paracingulum, and never within the parasulcus. The size of this species is small.
Dimensions:
The apical horn is 0-3 µm long, the antapical protrusion is about 10-12 µm long. 30 specimens measured.
Holotype: length 48 µm, width 35 µm, length of endocyst 38 µm.
Paratype 1991-NEP-2: length 62 µm, width 48 µm, length of endocyst 45 µm. Paratype 1991-NEP-3: length 57 µm, width 38 µm, length of endocyst 41 µm.
Overall cyst length (minimum-mean-maximum): 43 µm - 56 µm - 65 µm
Overall cyst width (minimum-mean-maximum): 37 µm - 43 µm - 51 µm.
Comparison: Tubotuberella owensii resembles most Tubotuberella egemenii (Gitmez 1970) Stover and Evitt 1978, from which it differs by being slightly smaller and stoibocavate or hypocavate.
Recorded occurrences: Tubotuberella owensii is found in the Late Oxfordian of the Fjerritslev-2 borehole (1266-68 m) and in the Oxfordian of the Harald Field in the Danish part of the Central Trough (Lulu-1 borehole at 11650 ft., West Lulu-1 at 11600 ft., West Lulu-2 at 12300 ft. See Nielsen and Japsen, 1991 for location of the two boreholes.