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Leptodinium quadrangulum
Leptodinium quadrangulum Yu Jingxian, 1982
Taxonomic senior synonym: Leptodinium impenseum, according to He Chengquan et al. (2009, p.107).
Holotype: Yu Jingxian, 1982, pl.4, fig.13
Age: Late Jurassic-Early Cretaceous
Description: Proximate cysts, subquadrilateral or rhombic in outline. Length equal to or lightly greater than width. Periphragm and endophragm closely appressed or somewhat separated. Surface has punctate or smally reticulate ornamentation. Parasutures low and flat. Paratabulation not too distinct. Paracingulum helical, 2 - 4 µm wide, decorated on edges with narrow ridges extending beyond cyst body exactly like two cingular horns. Epicyst smaller than or about equal to hypocyst. Precingular archeopyle, formed by loss of paraplate 3".
Size: Cysts 60 - 80 µm long and 70 - 82 µm wide.
Comparison: The new species is distinguished from other species within the genus by the fact that the paracingulum projects beyond the cyst exactly like two cingular horns.
Taxonomic senior synonym: Leptodinium impenseum, according to He Chengquan et al. (2009, p.107).
Holotype: Yu Jingxian, 1982, pl.4, fig.13
Age: Late Jurassic-Early Cretaceous
Description: Proximate cysts, subquadrilateral or rhombic in outline. Length equal to or lightly greater than width. Periphragm and endophragm closely appressed or somewhat separated. Surface has punctate or smally reticulate ornamentation. Parasutures low and flat. Paratabulation not too distinct. Paracingulum helical, 2 - 4 µm wide, decorated on edges with narrow ridges extending beyond cyst body exactly like two cingular horns. Epicyst smaller than or about equal to hypocyst. Precingular archeopyle, formed by loss of paraplate 3".
Size: Cysts 60 - 80 µm long and 70 - 82 µm wide.
Comparison: The new species is distinguished from other species within the genus by the fact that the paracingulum projects beyond the cyst exactly like two cingular horns.