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Pterospermopsis pelagica

Pterospermopsis pelagica Eisenack, 1954b, p.71, pl.12, figs.17–18. Emendation: Benedek and Gocht, 1981, p.59–61, as Thalassiphora pelagica.

NOW Thalassiphora. Originally Pterospermopsis, subsequently (and now) Thalassiphora, thirdly Disphaeria.
Taxonomic junior synonyms: Thalassiphora sueroi and Thalassiphora (as Disphaeria) balcanica, both according to Stover and Evitt (1978, p.194) — however, Sütő-Szentai (2000, p.162) retained Thalassiphora (as Spiniferites) balcanica. Pterocystidiopsis (as Thalassiphora) velata and Adnatosphaeridium (as Thalassiphora) patulum, both according to Benedek and Gocht (1981, p.59) — however, Lentin and Williams (1985, p.354) retained Thalassiphora patula and Brinkhuis and Biffi (1993, p.179) retained Pterocystidiopsis (as and now Thalassiphora) velata; Subathua sahnii, according to Lentin and Williams (1985, p.340) — however, Subathua sahnii is now considered to be a taxonomic junior synonym of Adnatosphaeridium (as and now Thalassiphora) patulum; Subathua spinosa, according to Lentin and Williams (1985, p.340) — however, Stover and Williams (1987, p.207) retained Subathua (as Thalassiphora) spinosa (now Thalassiphora simlaensis).

Holotype: Eisenack, 1954, pl.12, fig.17
Age: Late Eocene-Early Oligocene

Original description: Eisenack, 1954, p. 71
Diagnosis: A mostly ellipsoidal (rarely spherical) central body with a rather firm wall is suspended in or coalescing with a helmet-, flat saucer- or bell-shaped, bi-layered membrane, in such a way, that the longitudinal axis of the ellipsoid continues in the membrane. Mostly, a low, approximately sharp-edged keel runs over the convex side of this membrane in the direction of the longitudinal axis, terminating in a short tip at the rear margin of the membrane. On the (upper) outside of the central body, a mostly horseshoe-shapes hatch is developed in the front half.
Dimensions: Holotype: oval: 81:69 µm, membranes: ca. 170 µm, tip ca. 10 µm, hatch ca. 46 µm. Length and width of the central body vary between 78-98 µm and 60-78 µm, the diameter of the membrane between 144 and 196 µm. The height of the hatch between 36 and 46 µm.
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