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Alterbidinium bellulum
Alterbidinium bellulum, (He Chengquan, 1991), Lentin and Williams, 1993
This species was not validly published in Xu Jinli (1987, p.150), who gave the citation, "Alterbia bellula He (MS)".
Holotype: He Chengquan, 1991, pl.29, fig.12
Location and stratigraphy: Xinjiang province Wuqia county Wulukeqiati, wuyitake formation; Shandong province Guangyao county shahejie formation upper member 4
Age: Middle Eocene
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Original description: [He Chengquan, 1991]: (translated by Suning Hou, 07-01-2019):
Description:
The cyst is dorsal-ventral flattened and contours pentagonal, with straight edges, length slightly larger than width. It is divided into 2 nearly equal parts or slightly different parts by the cingulum: The epicyst is triangle, has a conical small apical horn, the top is blunt; the hypocyst is slightly larger, inverted trapezoid, and the two antapical horns are quite degenerated, only one is slightly displayed.
Cingulum is slightly deviated to the upper cyst, shallow flat, annular, width 8μm, the edge is marked by fine granular ridges.
The sulcus is unknown.
The outer wall surface is finely grained. The inner body contour is oval, thin wall, can be wrinkled, no significant ornamentation on the surface; It is widely separated from the outer wall.
Archeopyle obvious, intercalary. The operculum falls off.
Dimensions:
Cyst length 62μm, width 51μm, the inner body length 45μm, 37 μm.
Affinities/Comparison:
This new species is different from Alterbia ambigua with no noticeable elongation of the cyst; it differs from A. ovalis in a clearly defined pentagon outline (straight side).
This species was not validly published in Xu Jinli (1987, p.150), who gave the citation, "Alterbia bellula He (MS)".
Holotype: He Chengquan, 1991, pl.29, fig.12
Location and stratigraphy: Xinjiang province Wuqia county Wulukeqiati, wuyitake formation; Shandong province Guangyao county shahejie formation upper member 4
Age: Middle Eocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [He Chengquan, 1991]: (translated by Suning Hou, 07-01-2019):
Description:
The cyst is dorsal-ventral flattened and contours pentagonal, with straight edges, length slightly larger than width. It is divided into 2 nearly equal parts or slightly different parts by the cingulum: The epicyst is triangle, has a conical small apical horn, the top is blunt; the hypocyst is slightly larger, inverted trapezoid, and the two antapical horns are quite degenerated, only one is slightly displayed.
Cingulum is slightly deviated to the upper cyst, shallow flat, annular, width 8μm, the edge is marked by fine granular ridges.
The sulcus is unknown.
The outer wall surface is finely grained. The inner body contour is oval, thin wall, can be wrinkled, no significant ornamentation on the surface; It is widely separated from the outer wall.
Archeopyle obvious, intercalary. The operculum falls off.
Dimensions:
Cyst length 62μm, width 51μm, the inner body length 45μm, 37 μm.
Affinities/Comparison:
This new species is different from Alterbia ambigua with no noticeable elongation of the cyst; it differs from A. ovalis in a clearly defined pentagon outline (straight side).