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Nyktericysta inflata
From Fensome et al., 2019:
Nyktericysta inflata Dolby, 2019, VRp.5, pl.1, figs.9–11. Holotype: Dolby, 2019, pl.1, fig.9. Age: Aptian - early Albian.
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Synonymy. Nyktericysta sp. OS1, Dolby et al. 2013, pl. 1, fig. 6.
Holotype. Plate 1, figure 9.
Type locality. Suncor Liege 100/05-17-92-17W4, Alberta, 232.65 m, upper McMurray Formation.
Repository. National Collection of Type Invertebrate and Plant Fossils, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario, K1A 0E8, under curation number GSC 139225.
Diagnosis. A species of Nyktericysta in which the periphragm is widely separated from the endophragm, giving it an inflated appearance.
Description. Shape: The cyst is circumcavate and circular to rounded pentagonal with a generally rounded, rarely pointed apical prominence and two generally broad-based antapical horns. The periphragm is mostly separated from the endophragm except near the extremities of the antapical horns in most specimens. Lateral horns sometimes discernible as projections on the endophragm (Plate 1, figure 9) but usually absent on the periphragm.
Tabulation: Indicated only by archaeopyle sutures.
Archaeopyle: Apical; operculum attached, occasionally free.
Cingulum: Indicated on some specimens by folds in the periphragm.
Surface ornament: Endophragm smooth to finely granulose; periphragm smooth.
Dimensions [min (mode) max].
Equatorial diameter, periphragm: 51 (60) 68 mm (15 specimens). Holotype: 60 mm.
Equatorial diameter, endophragm: 45 (48) 53 mm.
Holotype: 50 mm.
Separation of periphragm: 5–14 mm.
Apical prominence: 4–18 mm (25 mm in rare cases).
Antapical horns: 7–16 mm (endophragm).
Derivation of name. Named for the inflated appearance of many of the specimens.
Comparison. Nyktericysta inflata differs from other species of Nyktericysta by the wide separation of the periphragm from the endophragm. The periphragm is attached near the tips of the antapical horns in most specimens. However, strongly inflated specimens may show complete separation and these could be confused with forms of Senoniasphaera.
Occurrence. Aptian to early Albian, middle and upper McMurray Formation and Clearwater Formation.
Nyktericysta inflata Dolby, 2019, VRp.5, pl.1, figs.9–11. Holotype: Dolby, 2019, pl.1, fig.9. Age: Aptian - early Albian.
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Synonymy. Nyktericysta sp. OS1, Dolby et al. 2013, pl. 1, fig. 6.
Holotype. Plate 1, figure 9.
Type locality. Suncor Liege 100/05-17-92-17W4, Alberta, 232.65 m, upper McMurray Formation.
Repository. National Collection of Type Invertebrate and Plant Fossils, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario, K1A 0E8, under curation number GSC 139225.
Diagnosis. A species of Nyktericysta in which the periphragm is widely separated from the endophragm, giving it an inflated appearance.
Description. Shape: The cyst is circumcavate and circular to rounded pentagonal with a generally rounded, rarely pointed apical prominence and two generally broad-based antapical horns. The periphragm is mostly separated from the endophragm except near the extremities of the antapical horns in most specimens. Lateral horns sometimes discernible as projections on the endophragm (Plate 1, figure 9) but usually absent on the periphragm.
Tabulation: Indicated only by archaeopyle sutures.
Archaeopyle: Apical; operculum attached, occasionally free.
Cingulum: Indicated on some specimens by folds in the periphragm.
Surface ornament: Endophragm smooth to finely granulose; periphragm smooth.
Dimensions [min (mode) max].
Equatorial diameter, periphragm: 51 (60) 68 mm (15 specimens). Holotype: 60 mm.
Equatorial diameter, endophragm: 45 (48) 53 mm.
Holotype: 50 mm.
Separation of periphragm: 5–14 mm.
Apical prominence: 4–18 mm (25 mm in rare cases).
Antapical horns: 7–16 mm (endophragm).
Derivation of name. Named for the inflated appearance of many of the specimens.
Comparison. Nyktericysta inflata differs from other species of Nyktericysta by the wide separation of the periphragm from the endophragm. The periphragm is attached near the tips of the antapical horns in most specimens. However, strongly inflated specimens may show complete separation and these could be confused with forms of Senoniasphaera.
Occurrence. Aptian to early Albian, middle and upper McMurray Formation and Clearwater Formation.