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Michouxdinium rhomboidale
Michouxdinium rhomboidale (He Chengquan, 1991, p.93, pl.35, figs.11–13) Williams et al., 2015, p.307.
Originally Kisselevia, subsequently Charlesdowniea, thirdly (and now) Michouxdinium? Questionable assignment: Williams et al. (2015, p.307).
Holotype: He Chengquan, 1991, pl.35, figs.11–12.
Age: middle Eocene.
Description from He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description: The outline is round diamond or nearly square, length and width are nearly equal. Upper cyst triangular, margin nearly straight or slightly convex, with or without a slightly pointed apical horn. The hypocyst is almost equal to the epicyst, semi-circular, slightly convex side, antapex smooth, lack of antapical horns. Two sides of the cyst waist are smooth, no lateral horns. TThe cingulum is fuzzy, located in the equatorial zone, concave on the side, about 7 .5μm wide. No sulcus displayed. Cyst wall has two layers, nearly equal thickness, the outer wall surface with a number of linear processes; processes are smooth, straight or curved, 5-12μm long. The ends are connected by not continuous enough linear trabecula, showing obvious fence onthe cyst contour; The process distribution is likely to be intra-plate, the local display of the fuzzy area, but the detailed tabulation can not be determined; the outer surface between the processes is smooth or with small particles. The inner body and the outer wall contours are the same, wall thickness is about 1μm, smooth surface; It and the outer wall are close to each other or separated by a narrow external cavate. The archeopyle is intercalry style, the outline is trapezoid. The operculum has been separated and preserved in place. Cyst length 83-96μm, width 75-96μm, the inner body length 74-85μm, width 68-87μm (measured 3), the holotype total length is 96μm, width 96μm, The inner body is 85μm long, 87μm wide.
Comparison:The new species is different from Kisselovia ornata subsp. Reticulata (Vozzhennikova) in that the cyst is round rhombus, lacking antapical horns and lateral horns.
Location and stratigraphy: Wuqia County Basebulak, Wulagen fm.
Originally Kisselevia, subsequently Charlesdowniea, thirdly (and now) Michouxdinium? Questionable assignment: Williams et al. (2015, p.307).
Holotype: He Chengquan, 1991, pl.35, figs.11–12.
Age: middle Eocene.
Description from He Chengquan, 1991, translated by Suning Hou, 07-01-2019
Description: The outline is round diamond or nearly square, length and width are nearly equal. Upper cyst triangular, margin nearly straight or slightly convex, with or without a slightly pointed apical horn. The hypocyst is almost equal to the epicyst, semi-circular, slightly convex side, antapex smooth, lack of antapical horns. Two sides of the cyst waist are smooth, no lateral horns. TThe cingulum is fuzzy, located in the equatorial zone, concave on the side, about 7 .5μm wide. No sulcus displayed. Cyst wall has two layers, nearly equal thickness, the outer wall surface with a number of linear processes; processes are smooth, straight or curved, 5-12μm long. The ends are connected by not continuous enough linear trabecula, showing obvious fence onthe cyst contour; The process distribution is likely to be intra-plate, the local display of the fuzzy area, but the detailed tabulation can not be determined; the outer surface between the processes is smooth or with small particles. The inner body and the outer wall contours are the same, wall thickness is about 1μm, smooth surface; It and the outer wall are close to each other or separated by a narrow external cavate. The archeopyle is intercalry style, the outline is trapezoid. The operculum has been separated and preserved in place. Cyst length 83-96μm, width 75-96μm, the inner body length 74-85μm, width 68-87μm (measured 3), the holotype total length is 96μm, width 96μm, The inner body is 85μm long, 87μm wide.
Comparison:The new species is different from Kisselovia ornata subsp. Reticulata (Vozzhennikova) in that the cyst is round rhombus, lacking antapical horns and lateral horns.
Location and stratigraphy: Wuqia County Basebulak, Wulagen fm.