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Circulodinium pentagonum
From Fensome et al., 2019:
Circulodinium pentagonum (He Chengquan, 1991, p.56, pl.9, figs.13–14) He Chengquan et al., 2009, p.272. Holotype: He Chengquan, 1991, pl.9, fig.13; Fensome et al., 2019a, fig.18J. NOW Tenua? Eisenack. Originally Canningia, subsequently Circulodinium, thirdly (and now) Tenua? Eisenack. Age: Late Cretaceous.
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Original description: [He Chengquan, 1991]: (translated by Suning Hou, 07-01-2019):
Description:
Cyst elongated pentagon, ventral dorsal flat, length larger than width. Upper cyst short conical, side slightly convex, apical horn slightly display; lower cyst inverted trapezoidal, the tail was significantly concave, two tails (convex> equal or unequal, one of the more developed for the nearly conical, about 10 μm.
Cingulum clear or fuzzy, narrow, width 5 μm, annular, slightly inferior to the lower cyst, decorated with fine ridges on the edge.
Sulcus fuzzy or not present. wall thin, granular surface.
Apical archeopyle, but usually not obvious. Operculum in-situ.
Dimensions:
Cyst length 49-72 μm, width 42. 5-60 μm (measured 2); Holotype length 72 μm, width 60 μm, an antapical horn about 10 μm.
Affinities:
this new species is morphologically similar to Canningia colliveri, which is produced in the Apuldi, Queensland, Australia. But the features of the surface ornamentation and cingulum are different, the latter having a spiny prickle-like surface process, blurred cingulums, only shown by side tiny concave.
Circulodinium pentagonum (He Chengquan, 1991, p.56, pl.9, figs.13–14) He Chengquan et al., 2009, p.272. Holotype: He Chengquan, 1991, pl.9, fig.13; Fensome et al., 2019a, fig.18J. NOW Tenua? Eisenack. Originally Canningia, subsequently Circulodinium, thirdly (and now) Tenua? Eisenack. Age: Late Cretaceous.
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Original description: [He Chengquan, 1991]: (translated by Suning Hou, 07-01-2019):
Description:
Cyst elongated pentagon, ventral dorsal flat, length larger than width. Upper cyst short conical, side slightly convex, apical horn slightly display; lower cyst inverted trapezoidal, the tail was significantly concave, two tails (convex> equal or unequal, one of the more developed for the nearly conical, about 10 μm.
Cingulum clear or fuzzy, narrow, width 5 μm, annular, slightly inferior to the lower cyst, decorated with fine ridges on the edge.
Sulcus fuzzy or not present. wall thin, granular surface.
Apical archeopyle, but usually not obvious. Operculum in-situ.
Dimensions:
Cyst length 49-72 μm, width 42. 5-60 μm (measured 2); Holotype length 72 μm, width 60 μm, an antapical horn about 10 μm.
Affinities:
this new species is morphologically similar to Canningia colliveri, which is produced in the Apuldi, Queensland, Australia. But the features of the surface ornamentation and cingulum are different, the latter having a spiny prickle-like surface process, blurred cingulums, only shown by side tiny concave.