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Impagidinium wuqiaense
Impagidinium wuqiaense He Chengquan, 1991, p.107-108, pl.5, fig.28; text-fig.14.
Holotype: He Chengquan, 1991, pl.5, fig.28; text-fig.14.
Age: Mid Eocene.
Description from He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description: cyst nearly round or oval, length slightly larger than the width, upper and lower cyst nearly equal, no apical antapicl horns. With clear plates, the edge is marked by variable height septa (or ridges), the septa may be higher at the gonal position (2-4μm), shown as ridges between the gonal positions, those on the upper cyst seem to be less developed than the upper cyst, only locally displayed, the edges of the plates are mostly ridges; The tabulation is 4', 6’’, 6c, 5'’', lp, 1’’". The first and fourth apex plates are small, equal, separated from each other by incomplete weak ridge; The second and third apex plates are larger, pentagonal; The sixth precingular plate is typically sub-triangular or pistol-shaped; The lower cyst plates are harder to observe. Cingulum strongly spiral, width around 8μm, the edge is like ridge, there are some short rod-spikes on the ridge; The ends of the cingulum miss each other at the ventral side about 2.5 cingulum width. The sulus is up to the first apical plate, plates are not developed in the sulcus, thee cyst wall thickness is about 1μm, the surface (including the septa) is fine granular. The acheopyle is precingular, P-type, formed by the movement of the third piece of the precingular plates (3"). The operculum is attached to the fourth precingular plate.
Cyst length 72.5μm, width 68μm.
Comparison: This new species is similar to Impagidinium aculeatum (Wall, 1967), but the former 6th precingular plate is large, sub-triangular or pistol-shaped, septum low, narrow cingulum, while the latter the sixth precingular plate is narrow strip, septa is high, cingulum wide; The difference from I. margaritiferum is that the latter sutural ridge is perforated; It is also different from I. sphaericum (Wall, 1967) for its lack of apical horn.
Formation and member: Ma Chaxian Basebulak ;. Wulagen group.
Holotype: He Chengquan, 1991, pl.5, fig.28; text-fig.14.
Age: Mid Eocene.
Description from He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description: cyst nearly round or oval, length slightly larger than the width, upper and lower cyst nearly equal, no apical antapicl horns. With clear plates, the edge is marked by variable height septa (or ridges), the septa may be higher at the gonal position (2-4μm), shown as ridges between the gonal positions, those on the upper cyst seem to be less developed than the upper cyst, only locally displayed, the edges of the plates are mostly ridges; The tabulation is 4', 6’’, 6c, 5'’', lp, 1’’". The first and fourth apex plates are small, equal, separated from each other by incomplete weak ridge; The second and third apex plates are larger, pentagonal; The sixth precingular plate is typically sub-triangular or pistol-shaped; The lower cyst plates are harder to observe. Cingulum strongly spiral, width around 8μm, the edge is like ridge, there are some short rod-spikes on the ridge; The ends of the cingulum miss each other at the ventral side about 2.5 cingulum width. The sulus is up to the first apical plate, plates are not developed in the sulcus, thee cyst wall thickness is about 1μm, the surface (including the septa) is fine granular. The acheopyle is precingular, P-type, formed by the movement of the third piece of the precingular plates (3"). The operculum is attached to the fourth precingular plate.
Cyst length 72.5μm, width 68μm.
Comparison: This new species is similar to Impagidinium aculeatum (Wall, 1967), but the former 6th precingular plate is large, sub-triangular or pistol-shaped, septum low, narrow cingulum, while the latter the sixth precingular plate is narrow strip, septa is high, cingulum wide; The difference from I. margaritiferum is that the latter sutural ridge is perforated; It is also different from I. sphaericum (Wall, 1967) for its lack of apical horn.
Formation and member: Ma Chaxian Basebulak ;. Wulagen group.