The Diplommatinidae of Fiji - a hotspot of Pacific land snail biodiversity (Caenogastropoda, Cyclophoroidea) Author Neubert, Eike Author Bouchet, Philippe text ZooKeys 2015 487 1 85 http://dx.doi.org/10.3897/zookeys.487.8463 journal article http://dx.doi.org/10.3897/zookeys.487.8463 1313-2970-487-1 4DA2B44E63514E61B9F258D33CBCE817 4DA2B44E63514E61B9F258D33CBCE817 Taxon classification Animalia Mesogastropoda Diplommatinidae Diancta basiplana sp. n. Figs 18-20 Type material. Holotype MNHN IM-2000-27416, paratypes MNHN/44 IM-2000-27417, NMBE 516870/10. Type locality: Viti Levu, Wailotua karst, 50-80 m, rainforest, -17.7582 178.4166, leg. Bouchet, 25-27.08.1998. Material. Viti Levu, Nakorosule limestone outcrop, 30 m, degraded forest, -17.7734 178.2517, leg. Bouchet & Dayrat, 16.02.1999, MNHN/180, NMBE 516881/20. Etymology. Latin noun basis = base, and adjective planus, -a, -um = flat. Diagnosis. Large sinistral shell, last whorl with a broad bulbous expansion, columellar plate forming a twisted tooth-like lamella, periomphalum flat. Description. Shell large, sinistral, shell colour dull brown; last whorl slightly constricted; protoconch big, bulbous obtuse with pitted microsculpture; umbilicus slit-like closed, periomphalum narrow, flat; last whorl with a broad bulbous expansion, aperture slightly shifted to the left and ascending, basis of the last whorl compressed; teleoconch sculpture of fine regularly spaced ribs, which become coarser on the last third of the last whorl; aperture almost rectangular, peristome doubled; apertural rims connected and detached from the last whorl, with a broad parietal shield; no pleats visible in the aperture; inside the shell with a columellar plate consisting of a twisted tooth-like lamella. Operculum corneous, with a small apophysis, OD = 0.63. Measurements. Holotype (Fig. 18): H = 3.94; D = 2.81; PH = 1.85; PD = 1.96; W = 5.5. Figures 18-20. Diancta basiplana sp. n. 18 Holotype MNHN IM-2000-27416, Viti Levu, Wailotua karst, H = 3.94 mm. 19 paratype, last whorl opened to show internal lamellae (enlarged, not to scale) 20 operculum 20a inner surface 20b outer surface. Figure 18 x 10, Figure 20 x 40 magnification. Distribution (Fig. 170). Central and eastern part of Viti Levu. Remarks. Diancta basiplana sp. n. is unmistakable because of its flat periomphalic base, and its twisted columellar plate.