Serrata orientalis, 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 : 401-402

Serrata orientalis n. sp.

Fig. 15

TYPE MATERIAL. — Holotype (dd) MNHN 20593 and 14 paratypes (lv and dd) MNHN 20594 , 1 paratype (dd) MMM, 1 paratype (dd) NMNZ.

TYPE LOCALITY. — Southeastern New Caledonia, 22°15’S, 167°15’E, 440 m [BIOCAL: stn DW 77] .

MATERIALEXAMINED.— SoutheasternNewCaledonia.BIOCAL: Loyalty Ridge. BIOCAL: stn DW 08, 20°34’S, 166°54’E, 435 m,

stn DW 77, 22°15’S, 167°15’E, 440 m, 1 lv (paratype MNHN), 16 2 dd as S. cf. orientalis .

dd (holotype, Fig. 15 and paratypes MNHN, MMM, NMNZ).

DISTRIBUTION. — Southeastern New Caledonia, live in 440 m, shells in 435-440 m.

DESCRIPTION. — Shell thick, subpyriform, opaque. Protoconch paucispiral, small, bulging, smooth. Spire mediumsized, produced, conical, whorls weakly convex. Aperture narrow, very oblique, widening anteriorly. Base slightly tapering. Outer lip thick, very oblique, reflected, shoulder moderately sloping, very rounded, lower half of outer edge nearly straight, outer margin wide, strongly thickened, gently rounded, not stepped, inner edge sinuous, slightly excavated anteriorly, bearing 11 subequal faint denticles, similar in size to the interspaces. Four moderate-sized columellar plaits, lowest one thinner, very oblique, nearly straight, second one long, oblique, sinuous, 2 upper ones less oblique, decreasing in size posteriorly.

Ground colour whitish (faded), with 2 ill-defined wide orange marks at about mid-height and on lower part of outer margin.

Dimensions: 5.10 x 2.90 mm.

Radula unknown.

REMARKS. — The type material of Serrata orientalis , collected at bathyal depths off southeastern New Caledonia, is closely similar to S. occidentalis . Serrata orientalis differs principally in its stouter shell outline, its narrower and more pointed spire, and its more reflected outer lip with a more sinuous inner edge.

The 2 shells from the Loyalty Ridge referred to S. orientalis (BIOCAL stn DW 08) are the same size as the type specimens and appear very similar. However they have a slightly more prominent spire and a more slender outline. Whether they belong to S. orientalis remains to be confirmed, as they could belong to another sibling species in the S. boucheti group.

ETYMOLOGY. — Latin orientalis (adj., eastern), referring to the geographical range of the species, off the eastern side of the New Caledonia mainland.