Serrata pupoides, Boyer, 2008

Boyer, Franck, 2008, The genus Serrata Jousseaume, 1875 (Caenogastropoda: Marginellidae) in New Caledonia, Mémoires du Muséum national d'Histoire naturelle 196, pp. 389-436 : 399-400

Serrata pupoides n. sp.

Fig. 12

TYPE MATERIAL. — Holotype (dd) MNHN 20589 and 2 paratypes (dd) MNHN 20590 .

TYPE LOCALITY. — Norfolk Ridge, 23°39’S, 168°00’E, 270-300 m [BATHUS 3: stn CH 801] .

MATERIAL EXAMINED. — Norfolk Ridge. BATHUS 3: stn CH 801, 23°39’S, 168°00’E, 270-300 m, 3 dd (holotype, Fig. 12 and paratypes) .

DISTRIBUTION. — Northern Norfolk Ridge , shells in from 270-300 m.

DESCRIPTION. — Shell ovate subcylindrical, solid, opaque. Protoconch paucispiral, medium-sized, bulging, smooth. Spire short, triangular, teat-like, whorls flat. Aperture narrow, subvertical, widening slightly towards the anterior. Base slightly tapering. Outer lip straight, vertical, moderately thickened, regular, shoulder faintly sloping, narrowly rounded, central and lower parts of the outer edge very weakly convex, subvertical, outer margin wide, moderately thickened, slightly rounded, stepped, inner edge straight, vertical, bearing 13 subequal, rather prominent denticles, somewhat smaller than the interspaces. Four thick, oblique columellar plaits, anterior one short, slightly sinuous, second one very long, nearly straight, 2 upper ones decreasing in size posteriorly, a small pleat just above fourth plait.

Ground colour whitish (faded), with orange shading ventrally at level of 2 upper columellar plaits and within the siphonal canal.

Dimensions: 4.85 x 2.10 mm.

Radula unknown.

REMARKS. — Despite its more cylindrical shell outline and its more regular labrum, Serrata pupoides is closely similar to S. ovata , especially in the proportions of the apex, the arrangement and size of the columellar plaits and the shape of the labial denticles. It differs from S. ovata principally in its more cylindrical shell outline, its more pointed spire and the less thickened posterior part of its outer lip. Serrata pupoides is sympatric with S. ovata on one seamount situated at 23°39’S- 23°41’S, 168°00’E- 168°01’E.

Serrata pupoides differs also from S. quadrifasciata in its stouter shell outline, its much stronger and more numerous labial denticles, including an isolated spur-like one along the siphonal canal, its thicker columellar plaits, and its small varix above the uppermost one, which is absent in S. quadrifasciata .

ETYMOLOGY. — Latin pupa (n., doll; by extension: ovate subcylindrical larval cases of insects) and –oides (comparative suffix: resemblance to), referring to the subcylindrical inflated outline of the shell.