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Oligosphaeridium xinjiangense

Oligosphaeridium xiniiangense He Chengquan, 1991

Holotype: He Chengquan, 1991, pl.26, fig.16; text-fig.23
Age: Paleocene-Middle Eocene

Description from He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description: the body nearly circular, thin wall, two layers contacted closely together, the outer wall surface fine granular. With 13 thin intratabular processes (not including the operculum and the sulcus area), hollow, straight or slightly curved, e brittle, and some are broken, basally and distally slightly expanded; Distally open, end edge thorn like (generally with a few spines, 1.3-5μm long); Process length and width can vary in different specimens, usually 11. 4-25μm long, 2-4μm wide; On the lower cyst ventral surface, there also appears to be 1-3 fine processes, which may be limited to the sulcus area. Tabulation 4', 6 ", 6'’', 1 p, 1"", 1-3s. Archeopyle apical, formed by the missing of apex, the edge angular. Operculum off. Total diameter of 70 -93.3 μ, body diameter 35-45.4μm (measured 4); the holotype total diameter about 70μm, body diameter 35μm, process length 17.5-22μm, width 2 - 4μm.
Comparison: this new species has similarities with the following species in the body size and the structure of the end of the processes, but the surface of Oligosphaeridium complex is smooth and the spines on the end of the processes are simple or bifurcated; The body of O. vasiformum or O. ?asterigerum (both of them have the same basic characteristics and the former may be the late synonyms of the latter) is sub-square, process occasionally with small piercing; O. reticulatum inner wall is reticulate; In O. cephalum, the width of the processes tapers distally, and the rapidly expands at the distal end. The more important difference is that none of these known species laks of the fine processes indicating the sulcus area
Location and stratigraphy: Wuqia County, Basebulak; Qimugen fm upper part of lower member and Wulagen fm.
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