Dicharax candrakirana, Nurinsiyah & Hausdorf, 2017

Nurinsiyah, Ayu Savitri & Hausdorf, Bernhard, 2017, Dicharax (?) candrakirana n. sp. (Gastropoda: Cyclophoridae) from Sempu Island, Indonesia, Zootaxa 4363 (4), pp. 589-591 : 589-591

Dicharax Kobelt & Möllendorff, 1900

Dicharax (?) candrakirana n. sp.

Diagnosis. Dicharax (?) candrakirana n. sp. is characterized by a small, depressed conical shell, with a smooth protoconch and an irregularly striated teleoconch, with spiral striae especially around the umbilicus, and with a short sutural tube about a quarter of a whorl posterior to the aperture from which 5–9 radial microtunnels extend.

Shell ( Fig. 1 ). Depressed conical; with 3 whorls separated by a deep suture. Protoconch low, smooth. Teleoconch irregularly striated, especially at the bottom side around the umbilicus with spiral striae, less distinct spiral striae are present also on the upper side close to the suture. Color whitish; subtranslucent. Last whorl rounded, with an indistinct constriction about a quarter of a whorl posterior to the aperture; posterior to the constriction with a short (0.25–0.3 mm long) sutural tube; below the tube with 5–9 radial microtunnels. Aperture almost circular, not crenulated; upper insertion of the peristome descending towards aperture; insertions of the peristome connected by a thick callus; peristome expanded, but not reflexed, strongly thickened inside. Umbilicus wide, eccentric.

Measurements (n = 8): shell diameter D: 2.0– 2.2 mm, mean 2.1 + 0.05 mm; shell height H: 1.25–1.3 mm, mean 1.25 + 0.05 mm; aperture (outer peristome) diameter da: 0.85–0.9 mm, mean 0.85 + 0.0 mm; aperture height ha: 0.85–0.9 mm, mean 0.85 + 0.0 mm; D/H: 1.63–1.71, mean 1.67 + 0.03.

Remarks. Kobelt (1902) classified Dicharax and Chamalycaeus Möllendorff, 1897 as subgenera of Alycaeus Gray, 1850 and distinguished Dicharax from Chamalycaeus by the position of the constriction and the presence of a swelling near the aperture. In contrast, Páll-Gergely et al. (2017) classified these two taxa as genera and distinguished Chamalycaeus from Dicharax based on the presence of elevated spiral striations on the teleoconch. Whereas D. candrakirana n. sp. would be classified in Chamalycaeus according to the diagnosis of Kobelt (1902), its classification is more problematic with regard to the classification of Páll-Gergely et al. (2017). There are distinct spiral lines at the bottom side around the umbilicus and less distinct spiral lines on the upper side close to the suture. However, the spiral lines are not elevated ridges as in Chamalycaeus . Páll-Gergely et al. (2017) found spiral striations also in a population of Dicharax depressus (Bavay & Dautzenberg, 1912) of Vietnam, which they nevertheless classified in Dicharax . We follow a recommendation of B. Páll-Gergely (pers. comm.) and classify the new species also preliminarily in Dicharax .

Dicharax (?) candrakirana n. sp. differs from Dicharax longituba ( Martens, 1864) of Java and Sumatra in the smaller shell with a shorter sutural tube, an only indistinct constriction without swelling, the lack of ribbing and the presence of spiral striae at the bottom side around the umbilicus. It differs from Chamalycaeus fruhstorferi ( Möllendorff, 1897) of Java and Chamalycaeus kessneri Vermeulen, 1996 of Bali and Nusa Penida in the smaller shell with fewer whorls and the lack of ribbing and elevated spiral striations.

Type material. Holotype: Indonesia, East Java: Malang, Sempu Island, limestone rocks in lowland rainforest at entrance of Kelabang Cave , 44 m a.s.l., 8°26'58"S 112°41'28"E ( MZB 19025, leg. A.S. Nurinsiyah & H. Fauzia 9 June 2014; measurements: D = 2.2 mm, H = 1.3 mm) . Paratypes: Indonesia, East Java: Malang, Sempu Island, limestone rocks at entrance of Kelabang Cave , 44 m a.s.l., 8°26'58"S 112°41'28"E ( MZB 19026/1; ZMH 133203 /2); Malang, Sempu Island , summit of Kembar Satu Hill, 65 m a.s.l., 8°27'20"S 112°41'28"E ( MZB 19027/2; ZMH 133204 /1); Malang, Sempu Island , Jembatan Anakan Hill, 46 m a.s.l., 8°27'05"S 112°41'28"E ( MZB 19028/1).

Type locality ( Fig. 2 ). Indonesia, East Java: Malang, Sempu Island, limestone rocks in lowland rainforest at entrance of Kelabang Cave , 44 m a.s.l., 8°26'58"S 112°41'28"E.

Distribution. The new species is known only from limestone rocks in lowland rainforest on Sempu Island in Indonesia.

Etymology. The species is named after Candra Kirana, a beautiful princess in the famous Indonesian folk tale ‘Keong Mas’, the ‘Golden Snail’.

Figures

FIGURE 1. Dicharax (?) candrakirana n. sp. Indonesia: Malang, Sempu Island, at entrance of Kelabang Cave (holotype MZB 19025).Scale bar = 1mm.

FIGURE 2. Type locality of Dicharax (?) candrakirana n. sp.: limestone rocks at entrance of Kelabang Cave on Sempu Island, Indonesia.