Serrata granum, 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 : 415

Serrata granum n. sp.

Fig. 38

TYPE MATERIAL. — Holotype (dd) MNHN 20618 .

TYPE LOCALITY. — Norfolk Ridge , 23°22’S, 168°01’E, 381-469 m [BATHUS 3: stn DW 827] .

MATERIAL EXAMINED. — Norfolk Ridge. BATHUS 3: stn DW 827, 23°22’S, 168°01’E, 381-469 m, 1 dd (holotype, Fig. 38) .

DISTRIBUTION. — Northern Norfolk Ridge , one shell in 381-469 m.

DESCRIPTION. — Shell ovate subpyriform, solid, opaque. Protoconch paucispiral, small, very low. Spire very low and blunt. Aperture very long, subvertical, regular. Base tapering. Outer lip reflected widely along all its length, arched; shoulder high, protruding, outer margin thick, wide, bevelled, stepped, inner edge bearing 8 small, low, blunt, labial denticles. Three oblique plaits visible on columellar edge, 2 lower ones longer than uppermost one, thick, closely spaced, third one smaller, thin, fourth, uppermost tiny plait situated within aperture.

Colour dirty whitish (faded).

Dimensions: 4.00 x 2.20 mm.

Radula unknown.

REMARKS. — In many respects, Serrata granum is similar to the French Polynesian species Serrata translata (Fig. 4), in its general oval outline, its very low spire and in several details such as the shape of the columellar plaits and of the outer lip. Serrata granum differs from S. translata in its more rounded outline, its smaller protoconch and its still lower spire, its longer aperture and its more reflected outer lip.

ETYMOLOGY. — Latin granum (n., grain), referring to the small size and oval outline of the shell.