Fig. 24
Scalpellum antarcticum Hoek, 1883: 95, pl. IV, figs 16–17.
Arcoscalpellum antarcticum: Newman & Ross, 1971: 50–51, fig. 17.
Teloscalpellum antarcticum: Zevina, 1981a: 377, fig. 293; Young, 2001b: 464, fig. 7.
Material examined. Holotype NHM UK 20013.1113, Stn 153: Indian Ocean, Antarctic (off Prince Elizabeth Land); 3065 m.
Diagnosis. Only the description of Hoek (1883) is available, but this does not provide details of the appendages.
Distrbution. Indian Ocean, Antarctic. Known depth 3065 m.
Remarks. The species is represented by a single specimen. It is distinguished by the particular form of the carinal latus that “also may present variations within the limits of a species” (Hoek, 1883).
Genus Trianguloscalpellum Zevina, 1978
Arcoscalpellum Hoek, 1907: 85 (part); Pilsbry, 1907a: 47; Newman & Ross, 1971: 42 (part).
Trianguloscalpellum Zevina, 1978b: 1349; Liu & Ren, 1985: 205.
Diagnosis. Capitulum with 13 or 14 plates; carinal latus triangular, umbo apical; inframedian latus triangular or rectangular, umbo apical, reaching upper latus.
Type species. Scalpellum balanoides Hoek, 1883.
Composition. 25 species.
Distribution. Worldwide, excluding Arctic. Known depth range 124 to 6135 m.
Remarks. Trianguloscalpellum is diagnosed by the possession of an apical umbo on all of the plates, and comprises two distinct species groups. One group (cited by Pilsbry (1907a) as Scalpellum velutinum (= Arcoscalpellum michelottianum) group) consists of species that attain a large size and have a thick and pilose cuticle. These species appear to be similar to some of the large species of the genera Litoscalpellum and Arcoscalpellum. The other group comprises species of Trianguloscalpellum that are very small and have a thin, often hairless cuticle. They are very different in appearance from the large species. The monophyletic status of this genus should be redefined by molecular analysis.