Diplommatina ristiae n. sp.

(Figs 12, 30; Table 1)

Diagnosis. Diplommatina ristiae n. sp. is characterized by its minute-sized, indistinctly ribbed shell, the lateral constriction of the last whorl and the ventrolaterally right position of the spiral palatal fold.

Shell (Fig. 30; Table 1). Dextral; spindle-shaped with conical early whorls and a narrowed last whorl; with 5.25–6 whorls separated by a deep suture; protoconch smooth; teleoconch with indistinct ribs (22–31 on the penultimate whorl; fewer on the last whorl) and a few very coarse ribs on the cervix; spiral striae between the ribs only locally visible; light corneous; subtranslucent; last whorl rounded, with a right lateral constriction; aperture subangular, angular at the transition from columellar to basal side; upper insertion of the peristome distinctly ascending towards aperture; insertions of the peristome connected by a partly detached callus; peristome distinctly expanded, thickened, doubled; aperture with a prominent columellar lamella, which remains high to ventrolaterally right inside the last whorl; with a long parietal lamella from lateral right to ventrolateral right inside the last whorl; with a spiral palatal fold ventrolaterally right inside the last whorl and with a short radial palatal fold laterally right; umbilicus closed. Shell height 1.63–2.0 mm, shell diameter 0.95–1.25 mm.

Remarks. Diplommatina ristiae n. sp. is most similar to D. perpusilla . For a comparison see there.

Type material. Holotype: Indonesia, Java, Central Java: Purworejo, Donorejo Village, near Seplawan Cave, 700 m a.s.l., 7°45'52''S 110°5'46''E (MZB 18884, leg. A.S. Nurinsiyah & T. Setiadi 9 January 2013, D = 1.25 mm, H = 1.85 mm). Paratypes: Indonesia, Java, West Java: Tasikmalaya, Setiawaras Village, near Sambawa Cave (Ranggawulung Cave), 361 m a.s.l., 7°35'02"S 108°10'57"E (MZB 18885/2; ZMH 133052 /1).— Central Java: Purworejo, Donorejo Village, near Seplawan Cave, 700 m a.s.l., 7°45'52''S 110°5'46''E (MZB 18886/4; ZMH 133053 /3).

Habitat. On shrubs and limestone rocks in agroforest at 360–700 m a.s.l.

Distribution (Fig. 12). Diplommatina ristiae n. sp. is endemic to West and Central Java.

Etymology. The species is named in honour of the Indonesian malacologist Ristiyanti Marwoto.