GENUS ARCUATOSCALPELLUM GEN. NOV.

FIGURE 4N–S

Type species

Scalpellum arcuatum Darwin, 1851b . Cretaceous, Albian–Cenomanian, UK.

Diagnosis

Basal scalpellines in which the carinolatus is slightly taller than broad, umbo apical, carinal margin convex, carina with median ridge; upper latus margin gently concave; inframedian latus surface not differentiat- ed; on the interior, the surfaces overlapping the carina and upper latus are similar; external sculpture with strong radial ridges, weak reticulation.

Derivation of name

In eponymous reference to the type species.

Referred species

Scalpellum (Arcoscalpellum) comptum Withers, 1910 and Scalpellum trilineatum Darwin, 1851b . Cretaceous.

Remarks

Material of the type species is illustrated here (Fig. 4M– S). Arcuatoscalpellum gen. nov. is the most basal scalpellid known, and ranges from Aptian to latest Maastrichtian in age. It shares many characters with Cretiscalpellum, including the sculpture and simple triangular morphology of the carinolatus.