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Senoniasphaera turensis
From Fensome et al., 2019:
Senoniasphaera turensis Vasilyeva in Andreeva-Grigorovich et al., 2011, p.34, pl.2, fig.6. Holotype: Andreeva-Grigorovich et al., 2011, pl.2, fig.6; Fensome et al., 2019a, fig.17J. Questionable assignment: Fensome et al. (2019a. p.44–45). Age: Danian.
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Original description: [Andreeva-Grigorovich et al., 2011] (translated from Russian):
Senoniasphaera turensis Vassilyeva sp. Nov. Tab. II, 6
Name: By location: section on the Tura River.
Diagnosis. Goniaulacoid circumcavate rounded cyst of intermediate size. Lateral and antapical protrusions not developed. Pericel not expressed.
Description: The pericyst is almost round, with barely visible antapical processes. The outline of the pericyst is uneven and finely wavy. The endocyst is round, matching the pericyst in shape. The pericoel is very narrow, slightly expanding in the antapical zone. The periphragm is fairly dense, transparent, forming wrinkles over the entire surface of the cyst and folds typical of this genus over the entire pericyst outline, which look like a row of lacy perforations in the pericoel zone. The periphragm is occasionally perforated over the entire surface. The endophragm is fairly dense, single-layered, smooth. The periarchaeopile is apical, type 1A. The operculum is attached or absent. The outline of the archaeopile is zigzag, uneven. Signs of paratabulation are weakly expressed by the position of the archaeopile; fine wrinkles of the periphragm indicate the position of the paracingulum.
Holotype. Plate II, 6. Prep. LD-1-60, collection of the Institute of Geology of the Urals of the Russian Academy of Sciences.
Location. Section of borehole LD-1 Lipovskaya, Tura River, Talitskaya suite (Sverdlovsk region, Lipovskoye settlement).
Dimensions (µm). Holotype: pericyst length 69.3; pericyst width - 66; endocyst length 59.4; endocyst width 56.0. Other specimens (4 specimens): pericyst length 72.0-68.2; pericyst width - 69.8-66.0; endocyst length 62.0-59.2; endocyst width - 58.2-56.0.
Comparison. It differs from other Senoniasphaera species in having a very narrow openwork pericelium.
Spreading. Russia, Middle Trans-Urals, Talitsky formation, Shadrinsky layers. Lower Paleocene (Denmark).
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Comments Fensome et al., 2019a:
Vasilyeva in Andreeva-Grigorovich et al. (2011, p. 34) provided the following description for this species:
Pericyst almost round, with barely noticeable antapical horns. Pericyst outline seems to be jagged, slightly wavy. Endocyst is round, coinciding in shape with pericyst. Pericoel is very narrow, slightly expanded antapically. Periphragm is quite dense, transparent and forms wrinkles over the whole surface and, typical for this species, has small folds over the whole pericyst outline, which look like a range of open perforations in the pericoel. Periphragm is occasionally perforated. Endophragm is quite dense, single-layered, smooth. Periarchaeopyle is apical (type tA). Operculum is attached or absent. Archaeopyle outline is uneven. Paratabulation is expressed by the archaeopyle; small wrinkles of the periphragm indicate the paracingulum. [Translation courtesy Alina Iakovleva, personal communucation]
It is unclear whether connections exist between the wall layers, both from the description and illustration. For this reason, because the pericoel is narrower than is typical for Senoniasphaera, and because the single specimen illustrated shows no unequivocal features of areoligeracean affinity, we question the assignment of this species to Senoniasphaera.
Stratigraphical occurrence. This species was originally described from the Danian of the southern Ural Mountains, Russia.
Senoniasphaera turensis Vasilyeva in Andreeva-Grigorovich et al., 2011, p.34, pl.2, fig.6. Holotype: Andreeva-Grigorovich et al., 2011, pl.2, fig.6; Fensome et al., 2019a, fig.17J. Questionable assignment: Fensome et al. (2019a. p.44–45). Age: Danian.
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Original description: [Andreeva-Grigorovich et al., 2011] (translated from Russian):
Senoniasphaera turensis Vassilyeva sp. Nov. Tab. II, 6
Name: By location: section on the Tura River.
Diagnosis. Goniaulacoid circumcavate rounded cyst of intermediate size. Lateral and antapical protrusions not developed. Pericel not expressed.
Description: The pericyst is almost round, with barely visible antapical processes. The outline of the pericyst is uneven and finely wavy. The endocyst is round, matching the pericyst in shape. The pericoel is very narrow, slightly expanding in the antapical zone. The periphragm is fairly dense, transparent, forming wrinkles over the entire surface of the cyst and folds typical of this genus over the entire pericyst outline, which look like a row of lacy perforations in the pericoel zone. The periphragm is occasionally perforated over the entire surface. The endophragm is fairly dense, single-layered, smooth. The periarchaeopile is apical, type 1A. The operculum is attached or absent. The outline of the archaeopile is zigzag, uneven. Signs of paratabulation are weakly expressed by the position of the archaeopile; fine wrinkles of the periphragm indicate the position of the paracingulum.
Holotype. Plate II, 6. Prep. LD-1-60, collection of the Institute of Geology of the Urals of the Russian Academy of Sciences.
Location. Section of borehole LD-1 Lipovskaya, Tura River, Talitskaya suite (Sverdlovsk region, Lipovskoye settlement).
Dimensions (µm). Holotype: pericyst length 69.3; pericyst width - 66; endocyst length 59.4; endocyst width 56.0. Other specimens (4 specimens): pericyst length 72.0-68.2; pericyst width - 69.8-66.0; endocyst length 62.0-59.2; endocyst width - 58.2-56.0.
Comparison. It differs from other Senoniasphaera species in having a very narrow openwork pericelium.
Spreading. Russia, Middle Trans-Urals, Talitsky formation, Shadrinsky layers. Lower Paleocene (Denmark).
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Comments Fensome et al., 2019a:
Vasilyeva in Andreeva-Grigorovich et al. (2011, p. 34) provided the following description for this species:
Pericyst almost round, with barely noticeable antapical horns. Pericyst outline seems to be jagged, slightly wavy. Endocyst is round, coinciding in shape with pericyst. Pericoel is very narrow, slightly expanded antapically. Periphragm is quite dense, transparent and forms wrinkles over the whole surface and, typical for this species, has small folds over the whole pericyst outline, which look like a range of open perforations in the pericoel. Periphragm is occasionally perforated. Endophragm is quite dense, single-layered, smooth. Periarchaeopyle is apical (type tA). Operculum is attached or absent. Archaeopyle outline is uneven. Paratabulation is expressed by the archaeopyle; small wrinkles of the periphragm indicate the paracingulum. [Translation courtesy Alina Iakovleva, personal communucation]
It is unclear whether connections exist between the wall layers, both from the description and illustration. For this reason, because the pericoel is narrower than is typical for Senoniasphaera, and because the single specimen illustrated shows no unequivocal features of areoligeracean affinity, we question the assignment of this species to Senoniasphaera.
Stratigraphical occurrence. This species was originally described from the Danian of the southern Ural Mountains, Russia.