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Tenua kukebaiense
From Fensome et al., 2019:
Tenua kukebaiense (Mao Shaozhi and Norris, 1988, p.31, pl.1, figs.6–8) Fensome et al., 2019a, p.48–49.
Holotype: Mao Shaozhi and Norris, 1988, pl.1, fig.7; Fensome et al., 2019a, fig.18G.
Originally Canningia, subsequently Circulodinium, thirdly (and now) Tenua Eisenack.
Taxonomic junior synonym (at specific rank): Cyclonephelium distinctum var. psilatum, according to Fensome et al. (2019a, p.48–49).
Age: Turonian–Santonian.
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Original description Mao Shaozhi and Norris, 1988
Diagnosis:
Cyst proximate, in dorsoventral view typically broadly ellipsoidal. Apical prominence protruding slightly from outline in one end; antapical end rounded or weakly diverging into two blunt lobations.
Autophragm thin, granulate, with numerous short nontabular isolated spines.
Archeopyle apical, type (tA)a or (tA).
Description:
Cyst subspherical to broadly ellipsoidal. Length and breadth of cyst almost equal, or latter slightly longer. Apical prominence short (1 to 3 µm), protruding indistinctly from outline. Antapex rounded or with slight concavity between two weak antapical lobations.
Autophragm thin and readily folded, folds usually trending approximately parallel to margin of cyst. Granulate wall surface covered with simple solid acuminate spines, 1 to 5 µm long, 1 to 2 µm across at their bases, and spaced 3 to 6 µm apart.
Archeopyle suture a zigzag line, with accessory sutures indicating six precingular plates. Operculum typically but not consistently attached. Cingulum usually indiscernible.
Sulcal notch offset to the left.
Indication of tabulation, other than archeopyle, absent.
Dimensions:
Length (including operculum) 46 to 54 µm (holotype 48 µm), width 45 to 61 µm (holotype 58 µm).
Affinities:
Canningia kukebaiensis differs from some other species of Canningia in having a subspherical to broadly ellipsoidal cyst with a small indistinct apical prominence and in its possession of a granulate autophragm covered with short, isolated, solid, and acuminate spines. C. colliveri (Cookson and Eisenack, 1960) has a cyst somewhat longer than broad, and its surface is granular or closely to sparsely spinate. C. minor (Cookson and Hughes, 1964) has a scabrate rather than granulate and spinate surface. C. scabrosa (Cookson and Eisenack, 1970) differs from C. kukebaiensis in having an irregular outline and some very short and narrow hairlike appendages.
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Comments Fensome et al., 2019a:
Cysts of this species are broadly ellipsoidal with an antapex that is rounded or with two “blunt lobations” (Mao Shaozi & Norris 1988, p. 31); the autophragm is granulate, with short, nontabular, isolated, acuminate spines, 1–5 μm long. This species thus conforms in morphology with Tenua, and so we re-assign it to that genus. The taxon described by Yu Jingxian & Zhang Wangping (1980) as Cyclonephelium distinctum var. psilatum appears to be conspecific with Tenua kukebaiensis and hence we propose the synonymy; kukebaiense is the senior epithet at specific rank. Tenua kukebaiense differs from Tenua attadalica primarily in its shape, the former having a rounded bowl-shaped central body, the latter having a more angular central body.
Stratigraphical occurrence. The type materials for both Tenua (as Canningia) kukebaiensis and Cyclonephelium distinctum subsp. psilatum are from the Turonian–Santonian of China.
Tenua kukebaiense (Mao Shaozhi and Norris, 1988, p.31, pl.1, figs.6–8) Fensome et al., 2019a, p.48–49.
Holotype: Mao Shaozhi and Norris, 1988, pl.1, fig.7; Fensome et al., 2019a, fig.18G.
Originally Canningia, subsequently Circulodinium, thirdly (and now) Tenua Eisenack.
Taxonomic junior synonym (at specific rank): Cyclonephelium distinctum var. psilatum, according to Fensome et al. (2019a, p.48–49).
Age: Turonian–Santonian.
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Original description Mao Shaozhi and Norris, 1988
Diagnosis:
Cyst proximate, in dorsoventral view typically broadly ellipsoidal. Apical prominence protruding slightly from outline in one end; antapical end rounded or weakly diverging into two blunt lobations.
Autophragm thin, granulate, with numerous short nontabular isolated spines.
Archeopyle apical, type (tA)a or (tA).
Description:
Cyst subspherical to broadly ellipsoidal. Length and breadth of cyst almost equal, or latter slightly longer. Apical prominence short (1 to 3 µm), protruding indistinctly from outline. Antapex rounded or with slight concavity between two weak antapical lobations.
Autophragm thin and readily folded, folds usually trending approximately parallel to margin of cyst. Granulate wall surface covered with simple solid acuminate spines, 1 to 5 µm long, 1 to 2 µm across at their bases, and spaced 3 to 6 µm apart.
Archeopyle suture a zigzag line, with accessory sutures indicating six precingular plates. Operculum typically but not consistently attached. Cingulum usually indiscernible.
Sulcal notch offset to the left.
Indication of tabulation, other than archeopyle, absent.
Dimensions:
Length (including operculum) 46 to 54 µm (holotype 48 µm), width 45 to 61 µm (holotype 58 µm).
Affinities:
Canningia kukebaiensis differs from some other species of Canningia in having a subspherical to broadly ellipsoidal cyst with a small indistinct apical prominence and in its possession of a granulate autophragm covered with short, isolated, solid, and acuminate spines. C. colliveri (Cookson and Eisenack, 1960) has a cyst somewhat longer than broad, and its surface is granular or closely to sparsely spinate. C. minor (Cookson and Hughes, 1964) has a scabrate rather than granulate and spinate surface. C. scabrosa (Cookson and Eisenack, 1970) differs from C. kukebaiensis in having an irregular outline and some very short and narrow hairlike appendages.
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Comments Fensome et al., 2019a:
Cysts of this species are broadly ellipsoidal with an antapex that is rounded or with two “blunt lobations” (Mao Shaozi & Norris 1988, p. 31); the autophragm is granulate, with short, nontabular, isolated, acuminate spines, 1–5 μm long. This species thus conforms in morphology with Tenua, and so we re-assign it to that genus. The taxon described by Yu Jingxian & Zhang Wangping (1980) as Cyclonephelium distinctum var. psilatum appears to be conspecific with Tenua kukebaiensis and hence we propose the synonymy; kukebaiense is the senior epithet at specific rank. Tenua kukebaiense differs from Tenua attadalica primarily in its shape, the former having a rounded bowl-shaped central body, the latter having a more angular central body.
Stratigraphical occurrence. The type materials for both Tenua (as Canningia) kukebaiensis and Cyclonephelium distinctum subsp. psilatum are from the Turonian–Santonian of China.