Taxon classification Animalia Mesogastropoda Diplommatinidae

Diancta trilamellata sp. n. Figs 44-46

Type material.

Holotype MNHN IM-2000-27433, paratypes MNHN/62 IM-2000-27434, NMBE 516871/10. Type locality: Viti Levu, Waivisa karst, 50-80 m, rainforest, -17.6879 178.4033, leg. Bouchet, 27.08.1998.

Etymology.

Latin numeral tres = three, and adjective lamellatus, -a, -um for possessing lamellae.

Diagnosis.

Shell sinistral, very small, teleoconch sculpture of coarse ribs, initially widely, then densely, spaced, last whorl ascending, aperture circular, detached from last whorl, with a palatal and a parietal lamella and broad columellar plate.

Description.

Shell sinistral, very small, whitish to yellowish; last whorl strongly constricted; protoconch broad, obtuse with a pitted microsculpture; umbilicus closed, very narrow periomphalum; teleoconch sculpture initially of coarse widely spaced ribs, changing to a more dense pattern on the central whorls, with a few very strong ribs on the last whorl; last whorl strongly ascending; aperture almost circular, not connected to the last whorl, peristome doubled and funnel-shaped, apertural rims connected; no dentition visible in the aperture by frontal view; internally with a palatal and a parietal lamella, columellar plate broad, subdivided into an inner and outer part, inner part with a slight notch.

Operculum corneous, flat, with a short apophysis, OD = 0.39.

Measurements.

Holotype (Fig. 44): H = 2.37; D = 1.91; PH = 1.13; PD = 1.17; W = 5.

Distribution

(Fig. 170). only known from the type locality.

Remarks.

Diancta trilamellata sp. n. superficially resembles Diancta martensi, but differs from it by its smaller size, the detached aperture, and the presence of a parietal lamella.