From Fensome et al., 2019:
Tenua dubia Jain and Millepied, 1975, p.152, pl.5, figs.75–76.
Holotype: Jain and Millepied, 1975, pl.5, fig.76; Fensome et al., 2019a, fig.18D.
NOW Cyclonephelium?. Originally (and now) Tenua Eisenack, subsequently Cyclonephelium, thirdly Cyclonephelium?.
Fensome et al. (2019a, p.47) retained this species in Tenua Eisenack
Age: Campanian–Maastrichtian.

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Original description: [Jain and Millepied, 1975]:

Tenua dubius sp. nov. (Pl. 5, Figs. 75-76)

Holotype - PI. 5, Fig. 76; Slide No. 8632-5.
Type locality - Bore hole no. CM-t, depth 1090 metres; Senegal Basin, W. Africa.
Horizon - Campanian-Maestrichtian.

Diagnosis - Shell slightly biconical with short rounded apical horn; antapical side obtusely rounded. Surface covercd with long, bifurcate processes. Epitract smoothly slops into an apical horn. Surface finely granulate. Archacopyle apical with angular detachment margin.

Measurements
Overall size: holotype: 78 x 70 μm, range: 70-80 x 62-75 μm
Process length: holotype: 10-15 μm, range: 10-15 μm

Comparison - Tenua dubius sp. nov. differs from Tenua anaphrissia (Sarjeant) Benedek (1972) in having only one type of characteristic long, bifurcate processes.

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Comments Fensome et al., 2019a:

Jain & Millepied (1975, p. 152) described this species as being “… covered with long, bifurcate processes. As the species lacks dorsoventral areas devoid of ornament and the ornament is less that 25% of the maximum cyst width, we retain it in Tenua.

Stratigraphical occurrence. Jain & Millepied (1975) recovered this species from the Campanian–Maastrichtian of western Africa.