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Stomodinium verrucosum
Stomodinium verrucosum He Chengquan, 1991
Now Xenicodinium. Originally Stomodinium, subsequently (and now) Xenicodinium. Holotype: He Chengquan, 1991, pl.13, fig.7, textfig.18
Age: Middle Eocene
Description from He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description: Cyst nearly circular or short oval, length slightly larger than the width, upper and lower cyst nearly equal, no apical antapical horns. Wall thickness about 4μm, stratification is not obvious, there are generally two types of ornamentations on the surface: one is tumor, shape and size variable, round tumor diameter 1.2-2.5μm, chunk tumors are larger, diameter 4-5μm; the height of two kinds of tumors is less than 1μm, the bases may be in contact with each other, the cyst contour wavelet, wall surface shows broken wrinkles partially due to corrosion. The other type is thin and short rod thorn-like processes, solid, oblique or curved, generally lodging, 2-4μm long, they are distributed along the pandasutural band (suture), the interval between each other is large on the outline; there are several process clusters, consisting of several (sometimes 8) processes of various lengths, these processes are located at gonal positions. The detailed tabulation can not be determined. Cingulum visible, marked by the short rod thorn-like processes along the equatorial area. Lack of sulcus. Archeopyle obvious, precingular, P-type, the outline of the horseshoe-shaped, obviously located above the cingulum, formed by the third precingular plate movement. Operculum preserved in situ. The total length 92-95μm, width 82-87.5μm, cyst length 88-93μm, width 77-80μm (measured 2); Holotype length 92μm, width 87.5μm , cyst length 88μm, width 80μm.
Comparison: The new species is very similar to Stomodinium crassum, both have incompletely seamed features, but the latter surface is wrinkled rather than nodular.
Now Xenicodinium. Originally Stomodinium, subsequently (and now) Xenicodinium. Holotype: He Chengquan, 1991, pl.13, fig.7, textfig.18
Age: Middle Eocene
Description from He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description: Cyst nearly circular or short oval, length slightly larger than the width, upper and lower cyst nearly equal, no apical antapical horns. Wall thickness about 4μm, stratification is not obvious, there are generally two types of ornamentations on the surface: one is tumor, shape and size variable, round tumor diameter 1.2-2.5μm, chunk tumors are larger, diameter 4-5μm; the height of two kinds of tumors is less than 1μm, the bases may be in contact with each other, the cyst contour wavelet, wall surface shows broken wrinkles partially due to corrosion. The other type is thin and short rod thorn-like processes, solid, oblique or curved, generally lodging, 2-4μm long, they are distributed along the pandasutural band (suture), the interval between each other is large on the outline; there are several process clusters, consisting of several (sometimes 8) processes of various lengths, these processes are located at gonal positions. The detailed tabulation can not be determined. Cingulum visible, marked by the short rod thorn-like processes along the equatorial area. Lack of sulcus. Archeopyle obvious, precingular, P-type, the outline of the horseshoe-shaped, obviously located above the cingulum, formed by the third precingular plate movement. Operculum preserved in situ. The total length 92-95μm, width 82-87.5μm, cyst length 88-93μm, width 77-80μm (measured 2); Holotype length 92μm, width 87.5μm , cyst length 88μm, width 80μm.
Comparison: The new species is very similar to Stomodinium crassum, both have incompletely seamed features, but the latter surface is wrinkled rather than nodular.