Serrata ovata, 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 : 395-396

Serrata ovata n. sp.

Fig. 7

TYPE MATERIAL. — Holotype (dd) MNHN 20582 and 2 paratypes (lv) MNHN 20583 .

TYPE LOCALITY. — Norfolk Ridge, 23°17’S, 168°14’E, 200-291 m [NORFOLK 1: stn DW 1724] .

MATERIAL EXAMINED. — Norfolk Ridge. SMIB 8: stn DW 170-172, 23°41’S, 168°00’E- 168°01’E, 230-290 m, 2 dd . — NORFOLK

1: stn DW 1724, 23°17’S, 168°14’E, 200-291 m, 2 lv (paratypes), 1 dd (holotype, Fig. 7).

DISTRIBUTION. — Northern Norfolk Ridge , live and shells in 230-290 m.

DESCRIPTION. — Shell ovate, solid, opaque. Protoconch paucispiral, medium-sized, low, smooth. Spire short, subtriangular, slightly blunted, whorls flat. Aperture narrow, very oblique, weakly widening towards base. Base slightly attenuated. Outer lip very oblique, thick posteriorly, narrowing anteriorly, shoulder moderately sloping, rounded, anterior part of outer edge oblique, faintly concave, outer margin wide, thickened, bevelled, not stepped, inner edge straight, bearing 11 subequal, prominent, rather widely spaced denticles. Four oblique columellar plaits, slightly thickened, second one slightly sinuous, 2 upper ones decreasing in size posteriorly, an additional small pleat just above fourth plait.

Ground colour pale horn-shaded orange, with 1 orange spiral line on upper third of last whorl, 2 orange spiral lines closely spaced on base of shell, all 3 lines making well-marked blotches on outer margin, intermediate line joining third columellar pleat, larger anterior line encompassing the 2 anterior columellar plaits.

Dimensions: 4.30 x 2.15 mm.

Radula unknown.

REMARKS. — Serrata ovata is very constant in shell morphology, proportions and decoration along its 24’ latitudinal distribution. Its general morphology is comparable with that of S. minima , especially the shape of the aperture and the outer lip. Serrata ovata differs from S. minima principally in its more inflated shell outline, its more attenuated spire, its thicker and less oblique columellar plaits, its thicker outer lip and its stronger labial denticles. The colour pattern of both species is similar. The known geographical locations of S. ovata are close to those of S. minima .

ETYMOLOGY. — Latin ovatus (adj., oval), referring to the egg-shaped outline of the shell.