Opisthostoma uranoscopium van Benthem Jutting, 1932

(Figs 19, 52; Table 3)

Opisthostoma uranoscopia Van Benthem Jutting, 1932: 201, pl.VII, fig. 1 a, b, c, 2, 3, 4 (Goenoeng TjibodaS (EState of Tjampea) near Buitenzorg, JaVa, 300 m. alt.).

Opisthostoma uranoscopium — Van Benthem Jutting 1948: 587, fig. 43–44.

Opisthostoma (Opisthostoma) uranoscopium — Zilch 1953: 16.

Diagnosis. Opisthostoma uranoscopium is characterized by an oblique cylindrical shell with a distinctly expanded aperture pointing apically.

Shell (Fig. 52; Table 3). Dextral; oblique cylindrical; first two whorls almost in one plane; third whorl forms a short oblique cylinder; fourth whorl slightly constricted at the commencement of the deviation in coiling, then ascending attached to the preceding whorl towards the aperture, which is turned upwards and forms an almost horizontal plane; with 3.5 whorls separated by a deep suture; protoconch smooth; teleoconch with oblique ribs (10– 23 per mm or 39–59 ribs on penultimate whorl); with spiral lines between the ribs; whitish; subtranslucent; last whorl rounded; aperture almost circular; upper margin of aperture is below the level of the apex; insertions of the peristome connected by a thick callus; peristome expanded, thickened, doubled; without lamellae or folds; umbilicus narrow; operculum thin, corneous, circular, paucispiral. Shell height 0.65–0.80 mm, shell width 0.70– 0.90 mm (without aperture) or 1.15–1.30 mm (with aperture).

Habitat. In leaf litter in forests on calcareous soils at 0–300 m a.s.l.

Type material. Indonesia, Java, West Java: Bogor, Ciampea, Mt. Cibodas, 300 m a.s.l., 6°33'S 106°41'E (syntypes of O. uranoscopium SMF 5505 /1, 104935/1; ZMA 136072 /4).

Other material. Indonesia, Java, Banten: Lebak, Sawarna, Mt. Kembang, 81 m a.s.l., 6°58'21"S 106°16'46"E (MZB 18881/4; ZMH 133050 /1).— West Java: Tasikmalaya, Karangnunggal, near Sela Dower cave, 237 m a.s.l., 7°40'00"S 108°07'00"E (MZB 18879/4; ZMH 133048 /2); Tasikmalaya, Karangnunggal, surroundings Pasir Taraje cave, 243 m a.s.l., 7°39'58"S 108°07'01"E (MZB 18880/9; ZMH 133049 /5).

Distribution (Fig. 19). Opisthostoma uranoscopium is endemic to Banten and West Java.

TABLE 3. Shell measurements of Opisthostoma species (in mm). Abbreviations: D = shell diameter (with aperture); D wa = shell diameter without aperture; H = shell height; max = maximum; min = minimum; n = number of measured specimens; rpw mm= number of ribs per mm on penultimate whorl; rpw= number of ribs on penultimate whorl; rbw mm = number of ribs per mm on last whorl; rbw= number of ribs on last whorl; SD= standard deviation; W = number of whorls.

Opisthostoma uranoscopium, n=21

Diagnosis. Opisthostoma sp. is characterized by an obliquely depressed shell with a slightly expanded aperture pointing to the upper side.

Shell (Fig. 53; Table 3). Dextral; obliquely depressed; first two whorls almost in a plane; third whorl forms a step below the plane; fourth whorl slightly constricted at the commencement of the deviation in coiling, ascending attached to the preceding whorl towards the aperture, which is turned upwards and forms an almost horizontal plane; with 4 whorls separated by a deep suture; protoconch smooth; teleoconch with oblique ribs (22 per mm on penultimate whorl); whitish; last whorl rounded; aperture almost circular; upper margin of aperture is below the level of the apex; insertions of the peristome connected by a thin callus; peristome slightly expanded, slightly thickened, doubled; without lamellae or folds; umbilicus a narrow hole. Shell height 0.65 mm, shell width 1.0 mm (without aperture) or 1.4 mm (with aperture).

Remarks. An Opisthostoma specimen that we found among a sample of Diplommatina sulcicollis from Kandang Badak is similar to O. uranoscopium, but differs from that species in the slightly broader (1.4 mm with aperture), oblique, depressed, more finely ribbed shell with a not so strongly expanded aperture and a smaller distance between inner and outer peristome. We do not name this species because only a single damaged specimen is available.

Habitat. In leaf litter on volcanic soil at 2400 m a.s.l.

Material. Indonesia, West Java: Kandang Badak, Mt. Gede, 2400 m a.s.l., 6°47'S 106°58'E (SMF 349026 /1). Distribution (Fig. 19). Opisthostoma sp. is endemic to West Java, where it has been found so far only on Mt. Gede.