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Apteodinium sparsum
Apteodinium sparsum, He Chengquan, 1991
Holotype: He Chengquan, 1991, pl.5, fig.36; text-fig.16.
Location and stratigraphy: Wuqia County Urukqiati; Kukebai fm mid member.
Age: Cenomanian
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Original description: [He Chengquan, 1991]: (translated by Suning Hou, 07-01-2019):
Description:
The cyst is dorsal-ventral flattened, outline suboval-ellipse, length larger than width, no apical antapical horn. Upper and lower cyst are almost the same in shape and size, high semi-circular.
Cingulum at equatorial position, obvious, spiral, width 7.5μm, the edge is marked by ridges;
The ridges are high, extending laterally out of contour 2 μm like a short spike, the ends of the cingulum staggered on the ventral side about two times of the cingulum width.
Sulcus narrow, limited to the lower cyst.
The autophragm is thin, the surface with the particles and sparse granular-rod or dentate processes, length 1-1 μm, there are more than 10 small processes visible on the outline; In addition, there are also 1-2 non-septa ridges locally.
Archeopyle large, precingular, P-type, outline horseshoe, formed by the third precingular plate movement. Operculum preserved in situ.
Dimensions:
Cyst length 77.5 μm, width 71 μm.
Affinities/Comparison:
This species is very similar to Apteodinium granorugosum in appearance. However, the former’s cyst is oval, length larger than width, dorsal-ventral flattened, the surface with granule and sparse granular-rod or dentate processes; The latter’s cyst wide-circular, width equals to length or larger, usually laterally pressed preservation, the surface is granular- short wrinkle-shaped particles, rough.
Holotype: He Chengquan, 1991, pl.5, fig.36; text-fig.16.
Location and stratigraphy: Wuqia County Urukqiati; Kukebai fm mid member.
Age: Cenomanian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [He Chengquan, 1991]: (translated by Suning Hou, 07-01-2019):
Description:
The cyst is dorsal-ventral flattened, outline suboval-ellipse, length larger than width, no apical antapical horn. Upper and lower cyst are almost the same in shape and size, high semi-circular.
Cingulum at equatorial position, obvious, spiral, width 7.5μm, the edge is marked by ridges;
The ridges are high, extending laterally out of contour 2 μm like a short spike, the ends of the cingulum staggered on the ventral side about two times of the cingulum width.
Sulcus narrow, limited to the lower cyst.
The autophragm is thin, the surface with the particles and sparse granular-rod or dentate processes, length 1-1 μm, there are more than 10 small processes visible on the outline; In addition, there are also 1-2 non-septa ridges locally.
Archeopyle large, precingular, P-type, outline horseshoe, formed by the third precingular plate movement. Operculum preserved in situ.
Dimensions:
Cyst length 77.5 μm, width 71 μm.
Affinities/Comparison:
This species is very similar to Apteodinium granorugosum in appearance. However, the former’s cyst is oval, length larger than width, dorsal-ventral flattened, the surface with granule and sparse granular-rod or dentate processes; The latter’s cyst wide-circular, width equals to length or larger, usually laterally pressed preservation, the surface is granular- short wrinkle-shaped particles, rough.