Serrata boucheti ( Boyer, 2001 ) 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 : 394

Serrata boucheti ( Boyer, 2001) comb. nov.

Figs 5, 63

Haloginella boucheti Boyer, 2001: 160-161 .

TYPE MATERIAL. — Holotype (lv) MNHN 20751 and 4 paratypes (dd) MNHN 20752 .

TYPE LOCALITY. — Banc Stylaster, guyots nord de la Ride de Norfolk, 23°38’S, 167°43’E, 430-452 m [SMIB 8: stn DW 167] .

MATERIAL EXAMINED. — Norfolk Ridge. SMIB 8: stn DW 167, 23°38’S, 167°43’E, 430-452 m, 1 lv (holotype, Fig. 5), 4 dd (paratypes) .

DISTRIBUTION. — Stylaster Bank, northern Norfolk Ridge , live and shells in 430-452 m.

DESCRIPTION. — Shell slender ovate fusiform, solid, subtranslucent. Protoconch paucispiral, medium-sized, slightly bulging, smooth. Spire moderate sized, conical, whorls slightly convex. Aperture narrow, subvertical, widening weakly anteriorly. Base moderately tapering. Outer lip slightly thickened, vertical, moderately reflected in centre, narrowing anteriorly. Shoulder sloping, outer edge making very slight angle below shoulder angle, intermediate area subvertical, gently curving towards base, outer margin wide, thickened, rounded, not stepped, inner edge slightly sinuous, vertical, bearing 11 tiny subequal denticles smaller than the interspaces. Four thin columellar plaits, 2 anterior ones oblique, sinuous, 2 posterior ones less oblique, decreasing in size posteriorly, a weak additional plait above fourth plait.

Ground colour pale orange, 2 narrow orange spiral bands distributed on upper whorl, 1 other spiral band on lower whorl, all 3 lines making well-marked orange blotches on outer margin, suprasutural zone intense white.

Dimensions: 5.15 x 2.45 mm.

Radula from 1 specimen (Fig. 63): uniserial, 13 plates about 53 Μm in width, bearing 31 subequal, short, blunt cusps.

REMARKS. — Serrata boucheti was described originally in the genus Haloginella , now considered a junior synonym of Serrata . It is known only from the type lot and seems to be restricted to the Stylaster Bank, on the northern Norfolk Ridge. The non-type material attributed to the species by Boyer (2001) belongs to S. tuii (PALEO-SURPRISE stn DW 1391: 1 adult dd), S. hians (BERYX 11 stn DW 35: 2 adult dd) and an undetermined species from the Banc Eponge, northern Norfolk Ridge (SMIB 8 stn DW 146-147: 1 juvenile dd).

Serrata boucheti is regarded as the typical species of a group of Serrata species occurring off southern and southeastern New Caledonia, on the Loyalty Ridge and on the Norfolk Ridge. The common characters defining this group are a tiny shell with a rather slender outline, a narrow aperture and a shell decoration generally made up of 3 to 4 orange bands more or less extending over the outer margin. Most of these species occur in the upper bathyal zone, and their radulae, when the data exist, seem to have the same kind of plate with subequal cusps, as is found in S. boucheti (Fig. 63) and in another species described below (Fig. 58).