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Spinidinium tabulare

Spinidinium ?tabulare He Chengquan, 1991, p.88, pl.2, figs.15–17. Holotype: He Chengquan, 1991, pl.2, fig.16. Questionable assignment: Sluijs et al. (2009, p.48). Age: Paleocene.

Description from He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description: The cyst is cornucavate, contour nearly biconic - pentagonal, body nearly circular, with a short triangular apical horn (about 5.5μm long, top rounded) and a non-centered antapical horn (Obtuse conical, ca. 5μm), and sometimes the other antapical horn is also slightly displayed. The epicyst is slightly larger than the hypocyst, bell-shaped; The hypocyst is nearly trapezoidal. Cingulum is at the equatorial position, obvious, annular, width 5-6μm, the edge is marked by the smooth fine ridge. The sulcus is not dispalyed. The cyst wall is thin, the surface of the outer wall is with a few longitudinal dentate ridge; the length of the teeth varies, and some are granular, and some longer, the longest is about 1μm, these dentate ridge is located at the edge of the plates, However, the tabulation is not identified, the surface of the plate is smooth or occasionally finely granular, sometimes with short rods processes at the apex, about 2 μm long. The inner body is nearly circular, the wall slightly thicker than the outer wall, the surface is smooth; Except for the corners, it is attached to the outer wall; The archeopyle is intercalary, trapezoidal, but the outline is often obscure. The operculum is off or in situ preserved. Cyst length 47.5-52.5μm, width 42.5μm, the inner body length 35-38μm, width 37-42μm (measured 3); Holotype length 47.5μm, width 42.5μm, inner body length 35μm, width 37μm, cingulum width 6μm.
Comparison: this new species is characterized by obvious tabulated outer wall surface, dentate ridge decorated plates edge , shorter and blunt antapical horns and different from the known species in the genus. Although Spinidinium clavum also has a tabulated outer wall, the cyst elongates to the spindle shape, different from this new species.
Location and stratigraphy: Wuqia County Basebulak; Qimugen fm, lower member.
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