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Tenua elongata
From Fensome et al., 2019:
(He Chengquan, 1991, p.55, pl.9, fig.1) Fensome et al., p.48. Holotype: He Chengquan, 1991, pl.9, fig.1; Fensome et al., 2019a, fig.18E. Originally Canningia, subsequently Circulodinium, thirdly (and now) Tenua? Eisenack. Questionable assignment: Fensome et al. (2019a. p.48). Age: Turonian.
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Original description: [He Chengquan, 1991]: (translated by Suning Hou, 07-01-2019):
Description:
Outline a little conical or elongated pentagon, body nearly circular a clear conical vertex(convex) extend from the top, blunt top. Antapical slightly concave, with two unequal antapical horns, of which the smaller one only tiny display.
Cyst wall relatively thin. Surface with separated short rod-shaped processes and a small amount of particles, length varies, 1-3.5 μm, generally 2 μm.
Archeopyle developed, apical type, (tA) type. The operculum is completely separated and stored in place.
Dimensions:
The holotype length 75 μm, width 62.5 μm.
Affinities:
this new species differs from Canningia senonica in that process are shorter, separated and unequally developed antapical horns, The latter species has longer processes and distantly connected forming an incomplete mesh pattern. The new species differs from C. Colliveri in possessing obviously elongated apical cyst and not deep antapical concave.
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Comments Fensome et al., 2019a:
We transfer this species to Tenua as its ornament appears to consist of an even covering of free-standing elements. However, the morphology of the holotype is unclear, and so we question the generic assignment and recommend that the name be restricted to the holotype.
Stratigraphical occurrence. He Chengquan (1991) recorded this species from the Turonian of Xinjiang, China.
(He Chengquan, 1991, p.55, pl.9, fig.1) Fensome et al., p.48. Holotype: He Chengquan, 1991, pl.9, fig.1; Fensome et al., 2019a, fig.18E. Originally Canningia, subsequently Circulodinium, thirdly (and now) Tenua? Eisenack. Questionable assignment: Fensome et al. (2019a. p.48). Age: Turonian.
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Original description: [He Chengquan, 1991]: (translated by Suning Hou, 07-01-2019):
Description:
Outline a little conical or elongated pentagon, body nearly circular a clear conical vertex(convex) extend from the top, blunt top. Antapical slightly concave, with two unequal antapical horns, of which the smaller one only tiny display.
Cyst wall relatively thin. Surface with separated short rod-shaped processes and a small amount of particles, length varies, 1-3.5 μm, generally 2 μm.
Archeopyle developed, apical type, (tA) type. The operculum is completely separated and stored in place.
Dimensions:
The holotype length 75 μm, width 62.5 μm.
Affinities:
this new species differs from Canningia senonica in that process are shorter, separated and unequally developed antapical horns, The latter species has longer processes and distantly connected forming an incomplete mesh pattern. The new species differs from C. Colliveri in possessing obviously elongated apical cyst and not deep antapical concave.
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Comments Fensome et al., 2019a:
We transfer this species to Tenua as its ornament appears to consist of an even covering of free-standing elements. However, the morphology of the holotype is unclear, and so we question the generic assignment and recommend that the name be restricted to the holotype.
Stratigraphical occurrence. He Chengquan (1991) recorded this species from the Turonian of Xinjiang, China.