Diancta densecostulata, Neubert, Eike & Bouchet, Philippe, 2015

Neubert, Eike & Bouchet, Philippe, 2015, The Diplommatinidae of Fiji - a hotspot of Pacific land snail biodiversity (Caenogastropoda, Cyclophoroidea), ZooKeys 487, pp. 1-85 : 14

Taxon classification Animalia Mesogastropoda Diplommatinidae

Diancta densecostulata sp. n. Figs 24-26

Type material.

Holotype MNHN IM-2000-27420, paratypes MNHN/283 IM-2000-27421, NMBE 516873/20. Type locality: Viti Levu, Wailotua karst, 50-80 m, rainforest, -17.7582 178.4166, leg. Bouchet, 25-27.08.1998.

Material.

Viti Levu, Tuvu karst, 50 m, dry forest, -17.9332 177.7067, leg. Bouchet, 23.08.1998, MNHN/11; Viti Levu, Wailotua, 115 m, -17.7664 178.4117, leg. Bouchet, 25.08.1998, MNHN/18.

Etymology.

Latin adjectives densus, -a, -um = close, and costulatus, -a, -um = ribbed.

Diagnosis.

Sinistral small shell, narrow periomphalum, fine regularly spaced teleoconch ribs, bipartite columellar plate, two palatal and one parietal lamella.

Description.

Shell sinistral, oval, small, brownish; last whorl constricted; protoconch broad, obtuse with a pitted microsculpture; umbilicus closed, concave and narrow periomphalum; teleoconch sculpture of fine regularly spaced ribs, in a dense pattern on the upper whorl, pattern more spacious with more coarse ribs on the last whorl; last whorl strongly ascending; aperture circular, connected to the last whorl, peristome funnel-shaped, simple; apertural rims connected, with a broad parietal shield; no dentition visible in the aperture by frontal view; inside with bipartite columellar plate, external part of the plate reduced to a basal knob, internal part a broad lamella, opposite a palatalis (visible in the aperture of fresh shells as an internal knob), a second palatalis just right above the columellar angle, and a parietal lamella present.

Operculum corneous, flat, internally with a small apophysis, DO = 0.38.

Measurements.

Holotype (Fig. 24): H = 2.33; D = 1.46; PH = 1.14; PD = 1.13; W = 5.5.

Distribution

(Fig. 170). Two localities quite far apart from each other on Viti Levu.

Remarks.

Diancta densecostulata sp. n. differs from Diancta macrostoma by its slightly smaller shell, the regular dense pattern of the teleoconch ribs, and the internal dentition.