Arinia yanseni, Hausdorf, 2017

Hausdorf, Bernhard, 2017, Revision of the Diplommatinidae (Gastropoda: Cyclophoroidea) from Java, Zootaxa 4312 (2), pp. 201-245 : 239

Arinia yanseni n. sp.

( Figs 8 , 18 , 48 ; Table 2)

Diagnosis. Arinia yanseni n. sp. is characterized by a cylindrical, widely ribbed shell with a furrow in the parietalpalatal angle of the aperture and a narrow umbilicus.

Shell ( Figs 8 , 48 ; Table 2). Dextral; cylindrical with conical early whorls; with 4.5–5 whorls separated by a deep suture; protoconch smooth; teleoconch with widely spaced ribs (27–43 on penultimate whorl); without distinct spiral striae between the ribs; whitish; subtranslucent; last whorl rounded, without constriction; aperture almost circular; upper insertion of the peristome slightly ascending towards aperture; insertions of the peristome connected by a distinct callus; peristome distinctly expanded, thickened, doubled; thickening of peristome indented in the parietal-palatal angle so that a furrow is formed; without lamellae; with a short, oblique palatal fold close to the suture dorsoventrally left inside the last whorl; umbilicus narrow; operculum thin, smooth, corneous, ovoidcircular, paucispiral. Shell height 1.55–2.0 mm, shell diameter 1.05–1.25 mm, umbilicus wide 0.1–0.2 mm.

Remarks. Arinia yanseni shares the furrow in the parietal-palatal angle of the aperture with some species from Borneo described by Vermeulen (1996). Among them, A. pertusa Vermeulen, 1996 , A. cylindrica Vermeulen, 1996 and A. clausa Vermeulen, 1996 are most similar to A. yanseni n. sp. with regard to shell shape and ribbing. These species differ from A. yanseni n. sp. in the more distinct angular fold delimiting the furrow in the parietal-palatal angle of the aperture. Moreover, the umbilicus of Arinia yanseni n. sp. is narrower than that of Arinia pertusa , but wider than that of Arinia cylindrica and Arinia clausa .

Habitat. In leaf litter in teak plantation, bamboo forest and secondary forest at 230–716 m a.s.l.

Type material. Holotype: Indonesia, Java, East Java: Rembang, Sumber Pacusen, 230 m a.s.l. 6°51'14"S 111°28'52"E ( MZB 18893, leg. A.S. Nurinsiyah & T. Setiadi 11 May 2015, D = 1.25 mm, H = 2 mm). Paratypes: East Java: Rembang , Sumber Pacusen , 230 m a.s.l. 6°51'14"S 111°28'52"E (BDJ/3; FW/3; MN/3; NHMUK 20170134 /5; MZB 18882/many; RMNH 5005193 /5; SMF 349068 /5; ZMB 121919 /5; ZMH 133051 /25). — West Java: Bibijilan, waterfall Sukabumi , 716 m a.s.l., 0 7°01'26"S 106°54'20"E ( MZB 18883/1). — Sumatra, Lampung: limestone area between Gua Tigal and Bukit Mapus, Waytuba, 4°23'S 104°25'E (BP 001/6; ME 2522/8; MZB 17981/15; ZMH 133305 /10; YSC 1488 /69).

Distribution ( Fig. 18 ). Arinia yanseni n. sp. is known from Java and southern Sumatra.

Etymology. The species is named in honour of the Indonesian malacologist Yansen Chen, who discovered this new species independently of us in southern Sumatra.

Figures

FIGURES 4 – 8. Opercula of Diplommatinidae. 4. Diplommatina javana Möllendorff, 1897, outer and inner Surface of opercula, WeSt JaVa: Majalengka, Argamukti, Mt. Ciremai National Park (MZB 13261). 5. Diplommatina auriculata Möllendorff, 1897, inner Surface of operculum, WeSt JaVa: Majalengka, Argamukti, Mt. Ciremai National Park (MZB 13258). 6. Palaina gedeana Möllendorff, 1897, outer and inner Surface of opercula, WeSt JaVa: Majalengka, Argamukti, Mt. Ciremai National Park (MZB 13244). 7. Palaina nubigena Möllendorff, 1897, outer Surface of operculum, WeSt JaVa: Cianjur, Kandang Badak (ZMA 68468). 8. Arinia yanseni n. sp., inner Surface of operculum, EaSt JaVa: Rembang, Sumber PacuSen (MZB 18882). Scale bar = 0.07 mm for FigS 3 – 6, 0.1 mm for Fig. 7.

FIGURES 15 – 19. DiStribution of Diplommatinidae in JaVa. 15. Diplommatina baliana Fulton, 1899. 16. Diplommatina diplostoma RenSch, 1931, Diplommatina nevilli (CroSSe, 1879) and Diplommatina canaliculata Möllendorff, 1887. 17. Diplommatina auriculata Möllendorff, 1897. 18. Palaina gedeana Möllendorff, 1897, Palaina nubigena Möllendorff, 1897 and Arinia yanseni n. sp. 19. Opisthostoma javanicum Van Benthem Jutting, 1932, Opisthostoma uranoscopium Van Benthem Jutting, 1932 and Opisthostoma sp.

FIGURES 46 – 48. Diplommatinidae from JaVa. 46. Palaina gedeana Möllendorff, 1897, JaVa (lectotype SMF 105100). 47. Palaina nubigena Möllendorff, 1897, WeSt JaVa: Cikuray (lectotype SMF 105095). 48. Arinia yanseni n. sp., EaSt JaVa: Rembang, Sumber PacuSen (holotype MZB 18893). Scale bar = 1.0 mm.