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Morkallacysta dalangshanensis
From Fensome et al., 2019:
Morkallacysta dalangshanensis (Yu Jingxian et al., 1981, p.259, pl.1, figs.7–10,15–16) He Chengquan et al., 2009, p.508. Holotype: Yu Jingxian et al., 1981, pl.1. fig.7. Originally Sanshuia, subsequently Geiselodinium, thirdly Saeptodinium, fourthly (and now) Morkallacysta. Age: Late Cretaceous.
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Sanshuia dalangshanensis
Description: Outline rhombic to broadly pentagonal, transversely elongated. Length and width as well as upper and lower tests nearly equivalent. Periphragm only, about 1 µm thick. Surface smooth or rough. Upper test triangular, 22 - 27.5 µm high. Apical horn is sharpened extension of upper test. Lower test trapezoidal, 19 - 20.7 µm high. Two antapical horns of approximately equal size, about 3 µm long. No tabulation displayed. No archaeopyle. Cingulum annular, slightly concave, 3 - 4.6 µm wide, decorated on edge with narrow microwave-shaped ridge that protrudes conspicuously. Sulcus triangular, with apex going to upper test. Sulcal edge embellished with a low flat ridge 2.3 - 4 µm wide. On cingulum near ventral region are 2 - 3 irregularly shaped nuclei", sometimes with tangled peripheral creases.
Size: Cysts 41.6 - 48 µm long and 35 - 46 µm wide. Holotype 45.5 x 39.1 µm.
Discussion: This species is distinguished from others in the genus by a ventral triangular sulcus decorated on the edge with a wide, flat ridge, and by the near equivalency of the upper and lower tests of the cyst.
Morkallacysta dalangshanensis (Yu Jingxian et al., 1981, p.259, pl.1, figs.7–10,15–16) He Chengquan et al., 2009, p.508. Holotype: Yu Jingxian et al., 1981, pl.1. fig.7. Originally Sanshuia, subsequently Geiselodinium, thirdly Saeptodinium, fourthly (and now) Morkallacysta. Age: Late Cretaceous.
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Sanshuia dalangshanensis
Description: Outline rhombic to broadly pentagonal, transversely elongated. Length and width as well as upper and lower tests nearly equivalent. Periphragm only, about 1 µm thick. Surface smooth or rough. Upper test triangular, 22 - 27.5 µm high. Apical horn is sharpened extension of upper test. Lower test trapezoidal, 19 - 20.7 µm high. Two antapical horns of approximately equal size, about 3 µm long. No tabulation displayed. No archaeopyle. Cingulum annular, slightly concave, 3 - 4.6 µm wide, decorated on edge with narrow microwave-shaped ridge that protrudes conspicuously. Sulcus triangular, with apex going to upper test. Sulcal edge embellished with a low flat ridge 2.3 - 4 µm wide. On cingulum near ventral region are 2 - 3 irregularly shaped nuclei", sometimes with tangled peripheral creases.
Size: Cysts 41.6 - 48 µm long and 35 - 46 µm wide. Holotype 45.5 x 39.1 µm.
Discussion: This species is distinguished from others in the genus by a ventral triangular sulcus decorated on the edge with a wide, flat ridge, and by the near equivalency of the upper and lower tests of the cyst.