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Palaeoperidinium striatum
Palaeoperidinium ?striatum He Chengquan, 1991, p.64, pl.1, figs.31–33; text-fig.7.
Holotype: He Chengquan, 1991, pl.1, fig.33; text-fig.7.
Questionable assignment: Evitt et al. (1998, p.48).
Age: Paleocene.
Location and stratigraphy: Ulugqat County Basebulak, lower Qimugen fm.
Description from He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description: Cyst ventral-dorsal flat, the outline pentagonal, length larger than width. The upper cyst is slightly larger than the lower cyst, conical, apical horn is not significantly differentiated, but there is a conical top extension, its top blunt or with hole; Lower cyst nearly trapezoidal, with two antapical horns, one is more developed , triangular or tapered, 7.5-9μm long, end blunt, the other is convex or almost completely degenerated.
Cingulum slightly offset in the lower cyst, ring form, width 5-7.5μm, the edge is marked by fine ridges;
Sulcus is fuzzy, limited to the lower cyst.
Thin cyst wall, the surface with vertical linear ridge or stripes, some ridge is formed by particles; Surface between the ridges is smooth.
The archeopyle combined type, (Atl3P) type, generally located in the flattened dorsal-ventral side of the cyst, the archeopyle main break crack from or almost through the top, an apical plate is included in the composition of the archeopyle. Operculum preserved in situ.
Dimensions: Cyst length 52.5-60μm, width 35-43 μm (measured 5); Holotype length 52.5μm, width 35μm, cingulum width 7μm.
Affinities/Comparison: This species is distinguished from Palaeoperidinium rugosum He, 1984 by features such as elongated pentagons instead of circular pentagons, vertical stripes rather than wrinkles.
Holotype: He Chengquan, 1991, pl.1, fig.33; text-fig.7.
Questionable assignment: Evitt et al. (1998, p.48).
Age: Paleocene.
Location and stratigraphy: Ulugqat County Basebulak, lower Qimugen fm.
Description from He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description: Cyst ventral-dorsal flat, the outline pentagonal, length larger than width. The upper cyst is slightly larger than the lower cyst, conical, apical horn is not significantly differentiated, but there is a conical top extension, its top blunt or with hole; Lower cyst nearly trapezoidal, with two antapical horns, one is more developed , triangular or tapered, 7.5-9μm long, end blunt, the other is convex or almost completely degenerated.
Cingulum slightly offset in the lower cyst, ring form, width 5-7.5μm, the edge is marked by fine ridges;
Sulcus is fuzzy, limited to the lower cyst.
Thin cyst wall, the surface with vertical linear ridge or stripes, some ridge is formed by particles; Surface between the ridges is smooth.
The archeopyle combined type, (Atl3P) type, generally located in the flattened dorsal-ventral side of the cyst, the archeopyle main break crack from or almost through the top, an apical plate is included in the composition of the archeopyle. Operculum preserved in situ.
Dimensions: Cyst length 52.5-60μm, width 35-43 μm (measured 5); Holotype length 52.5μm, width 35μm, cingulum width 7μm.
Affinities/Comparison: This species is distinguished from Palaeoperidinium rugosum He, 1984 by features such as elongated pentagons instead of circular pentagons, vertical stripes rather than wrinkles.