GENUS REGIOSCALPELLUM GEN. NOV.

FIGURES 2B, 6P–T, 10J, K, 11M–P, 18N–S

Diagnosis

Scalpellines in which a concave, internal upper latus surface and short carinal margin is present on the carinolatus, covered by epidermis; umbones of carinolatus incurved, lateral margin of carinolatus strongly convex.

Type species

Scalpellum regium Thomson, 1873 .

Derivation of name

In eponymous reference to the type species.

Referred species

Scalpellum darwini Hoek, 1883, Scalpellum gigas Hoek, 1883, Scalpellum moluccanum Hoek, 1883, Pollicipes maximus J. de C Sowerby, 1829, and Arcoscalpellum sanchezae Withers, 1953 .

Remarks

The distinctive R. maximum (Fig. 18N, O, P, S) is common in Cretaceous chalks and marginal marine deposits from the Coniacian to the Maastrichtian (Withers, 1935), and Regioscalpellum gen. nov. is represented in the Eocene of Cuba by Arcoscalpellum sanchezae Withers, 1953 .

GENUS GRAVISCALPELLUM FOSTER, 1980

FIGURES 2E–H, 13A–C

Type species

Scalpellum pedunculatum Hoek, 1883, by original designation.

Diagnosis

Scalpellinae in which the rostrolatera and inferomedian latera are very low in proportion to the height of the capitulum; carinolatera have an elongated rhomboidal outline, with a prominent ridge on the long axis; the umbonal region of the carinolatus is weakly involuted.

Included species

Scalpellum regina Pilsbry, 1907; Arcoscalpellum ungulatum Withers, 1953; Graviscalpellum grantmackiei Buckeridge, 1983 .

Remarks

Foster (1980: 526) established Graviscalpellum to include ‘Arcoscalpellids that are hermaphroditic, attain relatively large size and have lower latera about one tenth the height of the capitulum’. Subsequently, the genus was treated as a junior synonym of Anguloscalpellum Zevina, 1978b, because Zevina (1981) had included S. pedunculatum in that genus (e.g. Young, 2007); however, the type species of Anguloscalpellum, Scalpellum angulare Nilsson-Cantell, 1930, falls within the genus Weltnerium as redefined in this paper (trapezoidal scutum; deep, transversely elongated receptacle for dwarf male; rostrum with broad triangular external surface), and is evidently not related closely to S. pedunculatum . Therefore, Graviscalpellum is resurrected from synonomy to include both the extant G. regina (Pilsbry, 1907) and a number of fossil species from the Oligocene–Miocene of New Zealand (Buckeridge, 1983). The molecular phylogeny of Lin et al. (2015: fig. 3) shows G. regina and G. pedunculatum as closly related taxa.