Back
Morkallacysta dalangshanensis
Morkallacysta dalangshanensis (Yu Jingxian et al., 1981, p.259, pl.1, figs.7–10,15–16) He Chengquan et al., 2009, p.508.
Originally Sanshuia, subsequently Geiselodinium, thirdly Saeptodinium, fourthly (and now) Morkallacysta.
Holotype: Yu Jingxian et al., 1981, pl.1. fig.7.
Age: Late Cretaceous.
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 Ám thick. Surface smooth or rough. Upper test triangular, 22 - 27.5 Ám high. Apical horn is sharpened extension of upper test. Lower test trapezoidal, 19 - 20.7 Ám high. Two antapical horns of approximately equal size, about 3 Ám long. No tabulation displayed. No archaeopyle. Cingulum annular, slightly concave, 3 - 4.6 Ám 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 Ám wide. On cingulum near ventral region are 2 - 3 irregularly shaped nuclei", sometimes with tangled peripheral creases.
Size: Cysts 41.6 - 48 Ám long and 35 - 46 Ám wide. Holotype 45.5 x 39.1 Ám.
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.
Originally Sanshuia, subsequently Geiselodinium, thirdly Saeptodinium, fourthly (and now) Morkallacysta.
Holotype: Yu Jingxian et al., 1981, pl.1. fig.7.
Age: Late Cretaceous.
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 Ám thick. Surface smooth or rough. Upper test triangular, 22 - 27.5 Ám high. Apical horn is sharpened extension of upper test. Lower test trapezoidal, 19 - 20.7 Ám high. Two antapical horns of approximately equal size, about 3 Ám long. No tabulation displayed. No archaeopyle. Cingulum annular, slightly concave, 3 - 4.6 Ám 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 Ám wide. On cingulum near ventral region are 2 - 3 irregularly shaped nuclei", sometimes with tangled peripheral creases.
Size: Cysts 41.6 - 48 Ám long and 35 - 46 Ám wide. Holotype 45.5 x 39.1 Ám.
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.