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Apiculadinium ovatum
Apiculadinium ovatum, Yu Jingxian et al., 1981
NOW Laciniadinium. Originally Apiculadinium, subsequently (and now) Laciniadinium.
Holotype: Yu Jingxian et al., 1981, pl.1, fig.36.
Age: Late Cretaceous
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Original description: [Yu Jingxian et al., 1981]:
Description:
Outline pyriform, oval. Periphragm present. Only apex and antapex show periphragm and endophragm. Endocyst boundary unclear, closely appressed to periphragm. Surface has granules and several irregular creases. Sometimes a few short rhomboidal spines can be observed antapically. Upper test subtriangular, larger than or equal to lower test, 23.8 - 30.6 µm high. Apical horn is extension of upper test; circular apical pore at end. Lower test semicircular or roundly triangular, 13 - 23.4 µm high.
Antapical horns undeveloped.
Cingulum annular or slightly spiraled, concave, 2.3 - 6 µm wide, ornamented with narrow ridge on edge that projects beyond contour line.
Sulcus narrow and long or large and wide, passing from lower test across cingulum to upper test. Observable in ventral section of upper test and girdle region are 3 - 4 "nuclei", 3 - 6 µm in diameter.
No tabulation or archaeopyle observed.
Dimensions:
Size: Cysts 40.8 - 57.5 µm long, 30 - 47.6 µm wide; Holotype 52.9 x 45.5 µm.
Discussion:
With its conspicuously oval outline, lack of antapical horns, developed tabulation and archaeopyle, and long sulcus, the apex of which reaches the upper test, this species is not easily confused with other genera and species.
NOW Laciniadinium. Originally Apiculadinium, subsequently (and now) Laciniadinium.
Holotype: Yu Jingxian et al., 1981, pl.1, fig.36.
Age: Late Cretaceous
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Yu Jingxian et al., 1981]:
Description:
Outline pyriform, oval. Periphragm present. Only apex and antapex show periphragm and endophragm. Endocyst boundary unclear, closely appressed to periphragm. Surface has granules and several irregular creases. Sometimes a few short rhomboidal spines can be observed antapically. Upper test subtriangular, larger than or equal to lower test, 23.8 - 30.6 µm high. Apical horn is extension of upper test; circular apical pore at end. Lower test semicircular or roundly triangular, 13 - 23.4 µm high.
Antapical horns undeveloped.
Cingulum annular or slightly spiraled, concave, 2.3 - 6 µm wide, ornamented with narrow ridge on edge that projects beyond contour line.
Sulcus narrow and long or large and wide, passing from lower test across cingulum to upper test. Observable in ventral section of upper test and girdle region are 3 - 4 "nuclei", 3 - 6 µm in diameter.
No tabulation or archaeopyle observed.
Dimensions:
Size: Cysts 40.8 - 57.5 µm long, 30 - 47.6 µm wide; Holotype 52.9 x 45.5 µm.
Discussion:
With its conspicuously oval outline, lack of antapical horns, developed tabulation and archaeopyle, and long sulcus, the apex of which reaches the upper test, this species is not easily confused with other genera and species.