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Sentusidinium minutum
Sentusidinium minutum He Chengquan, 1991
Holotype: He Chengquan, 1991, pl.15, fig.4
Age: Late Senonian-early Eocene
Description by He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description： Central body outline oval, length larger than width, no apical and antapical horns. The wall is thin and covered by a large number of thin spine. Spines are separated, variable in lengths, solid, straight or banded, with a blunt or pointed end. Wall surfaces between spines are finely grained. The archeopyle, (tA) type, from the loss of the apical area, the edge angular (sometimes "Z" shaped, with obvious "V" incision). Operculum is lost or in situ preserved. The length of central body (apical parts not present) is 36μm- (complete specimen) 42.5μm, width 35-40μm, spine length 3 - 7μm; Holotype length (apical parts not present) 36μm, width 35μm, spine length 3-7μm.
Comparison: The new speciesis characterized with small body, central body outline oval, spines thin and pointed etc. The following several species are similar to it, however, individuals of Sentusidinium eisenackii (Boltenhagen) and S. spiculatum Yu et Zhang (Yu et al., 1980, p. 107, pl. I. figs, 15, 16) have larger bodies, circular central boday and short spines. The archeopyle edge of Kallosphaeridium minor (Jiabo, 1978)is smooth, non-zigzag，operculum attached and a nearly circular central body.
Location and stratigraphy: Ulugqat County Basebulak west; Wuyi Tucker fm bottom and Zimorgan fm top.
Holotype: He Chengquan, 1991, pl.15, fig.4
Age: Late Senonian-early Eocene
Description by He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description： Central body outline oval, length larger than width, no apical and antapical horns. The wall is thin and covered by a large number of thin spine. Spines are separated, variable in lengths, solid, straight or banded, with a blunt or pointed end. Wall surfaces between spines are finely grained. The archeopyle, (tA) type, from the loss of the apical area, the edge angular (sometimes "Z" shaped, with obvious "V" incision). Operculum is lost or in situ preserved. The length of central body (apical parts not present) is 36μm- (complete specimen) 42.5μm, width 35-40μm, spine length 3 - 7μm; Holotype length (apical parts not present) 36μm, width 35μm, spine length 3-7μm.
Comparison: The new speciesis characterized with small body, central body outline oval, spines thin and pointed etc. The following several species are similar to it, however, individuals of Sentusidinium eisenackii (Boltenhagen) and S. spiculatum Yu et Zhang (Yu et al., 1980, p. 107, pl. I. figs, 15, 16) have larger bodies, circular central boday and short spines. The archeopyle edge of Kallosphaeridium minor (Jiabo, 1978)is smooth, non-zigzag，operculum attached and a nearly circular central body.
Location and stratigraphy: Ulugqat County Basebulak west; Wuyi Tucker fm bottom and Zimorgan fm top.