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Tenua apiculata
From Fensome et al., 2019:
Tenua ?apiculata (Jain and Garg in Jain et al., 1984, p.71–72, pl.2, figs.27–29) Fensome et al., 2019a, p.46.
Holotype: Jain et al., 1984, pl.2, fig.27; Fensome et al., 2019a, fig.17N.
Originally Canningia, subsequently (and now) ?Tenua.
Questionable assignment: Fensome et al. (2019a, p.46).
Age: Kimmeridgian–early Tithonian.
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Original description: [Jain and Garg, 1984, p.71]:
Diagnosis:
Cyst lenticular, autophragm only; processes short, distally truncate to bifid, distantly placed; crest well developed, surface granular; paracingulum faintly indicated; apex pointed, apical horn short; antapex broad. Bilobed.
Archeopyle apical (tA); principal archeopyle suture zig-zag, with six precingular paraplates.
Dimensions:
Holotype Range, Overall cyst size 80x66 µm 66-80x60-70 µm, Process length 4 µm 2-4 µm
Affinitis:
Spiti specimens show mixed characters of Canningia and Aptea. Antapical bilobation puts it closer to Canningia whereas autophragm ornamentation with curved ridges suggest affinity with Aptea. Due to lack of antapical horn, the forms are presently described under Canningia. The present specimens are devoid of any intercalary paraplate. The concept of Dörhöfer and Davies (1980, p. 36) is presently not acceptable.
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Comments Fensome et al., 2019a:
From the illustrations in Jain et al. (1984), this species appears to be an areoligeracean despite its early age, with the type having an asymmetrical antapex. It has a single wall layer and is thus not attributable to Canningia under the current concept of that genus. In the diagnosis, Jain & Garg in Jain et al. (1982, p. 71) noted the following: “processes short, distally truncate to bifid, distantly placed; crest well developed …”. In their remarks, the authors refer to ornamentation “with curved ridges”. Although the spines are evident on the illustrations and appear to be more or less uniform in distribution, but the nature of the “crest” and “curved ridges” are unclear, we tentatively transfer this species to Tenua and suggest that it be restricted to the type material until its morphology can be clarified.
Stratigraphical occurrence. The type material of Tenua? apiculata is from the Kimmeridgian to lower Tithonian of India.
Tenua ?apiculata (Jain and Garg in Jain et al., 1984, p.71–72, pl.2, figs.27–29) Fensome et al., 2019a, p.46.
Holotype: Jain et al., 1984, pl.2, fig.27; Fensome et al., 2019a, fig.17N.
Originally Canningia, subsequently (and now) ?Tenua.
Questionable assignment: Fensome et al. (2019a, p.46).
Age: Kimmeridgian–early Tithonian.
---------------------------------------------------------------------------------------------------
Original description: [Jain and Garg, 1984, p.71]:
Diagnosis:
Cyst lenticular, autophragm only; processes short, distally truncate to bifid, distantly placed; crest well developed, surface granular; paracingulum faintly indicated; apex pointed, apical horn short; antapex broad. Bilobed.
Archeopyle apical (tA); principal archeopyle suture zig-zag, with six precingular paraplates.
Dimensions:
Holotype Range, Overall cyst size 80x66 µm 66-80x60-70 µm, Process length 4 µm 2-4 µm
Affinitis:
Spiti specimens show mixed characters of Canningia and Aptea. Antapical bilobation puts it closer to Canningia whereas autophragm ornamentation with curved ridges suggest affinity with Aptea. Due to lack of antapical horn, the forms are presently described under Canningia. The present specimens are devoid of any intercalary paraplate. The concept of Dörhöfer and Davies (1980, p. 36) is presently not acceptable.
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Comments Fensome et al., 2019a:
From the illustrations in Jain et al. (1984), this species appears to be an areoligeracean despite its early age, with the type having an asymmetrical antapex. It has a single wall layer and is thus not attributable to Canningia under the current concept of that genus. In the diagnosis, Jain & Garg in Jain et al. (1982, p. 71) noted the following: “processes short, distally truncate to bifid, distantly placed; crest well developed …”. In their remarks, the authors refer to ornamentation “with curved ridges”. Although the spines are evident on the illustrations and appear to be more or less uniform in distribution, but the nature of the “crest” and “curved ridges” are unclear, we tentatively transfer this species to Tenua and suggest that it be restricted to the type material until its morphology can be clarified.
Stratigraphical occurrence. The type material of Tenua? apiculata is from the Kimmeridgian to lower Tithonian of India.