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Phelodinium spinatum

Phelodinium? spinatum He Chengquan, 1991

He Chengquan, 1991 questionably included this species in Phelodinium.
Holotype: He Chengquan, 1991, pl.2, fig.25
Age: Paleocene

Description from He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description: The cyst is dorsal ventral flattened, outline elongated perdiniacean. The sides of the waist strongly protrude. Upper and lower cyst are of equal size; Upper cyst conical, a long apical horn extends from the top, up to 20μm, the top blunt, crispy, usually broken; Lower cyst inverted trapezoidal, two antapical horns diverging, nearly equal size, tapered, distally extremely solid, rod-like, end blunt, length 15-20μm. Cingulum shallow and flat, annular, 5-7μm wide, equatorial position, the edge marked by the fine ridges. Sulcus obvious, narrow trapezoidal or fuzzy, limited to the lower cyst. No paratabulation. Inner body may be lacking. The cyst wall delamination is not clear, short rod-like processes and particles are uniformly distributed on the surface. Processes length is usually about 2.5μm. The archeopyle is unknown (perhaps intercalary). Cyst length 62.5-90μm, width 42.5-54μm (measured 5); Holotype length 85μm, width 54μm, apical horn about 20μm, antapical horns length 15μm, cingulum width 5μm, processes length 2. 5μm.
DISCUSSION: This type of specimen is difficult to be classified as Palaeoperidinium, Phelodinium, Vozzhennikovia, or Spinidinium because of its unclear archeopyle, unclear inner body, short rod-like surface and two equal antapical horns. It is here categorized as Phelodinium only on the basis of its morphology. The new species is distinguished from Phelodinium spinocapitatum by short rod-shaped processes throughout the entire surface, the latter having only rod-shaped processes at the apical horn.
Location and stratigraphy: Ulugqat County Basebulak, Qimugen fm the lower member.

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