Clostophis infantilis Páll-Gergely, 2020

Páll-Gergely, Barna, Hunyadi, András, Grego, Jozef, Reischütz, Alexander, Buczkó, Krisztina & Vermeulen, Jaap J., 2020, Clostophis Benson, 1860, is not a monotypic diplommatinid but a speciose hypselostomatid (Gastropoda: Eupulmonata), with descriptions of six new species, Raffles Bulletin of Zoology 68, pp. 350-368 : 358

Clostophis infantilis Páll-Gergely , new species

( Fig. 5 )

Type material. Holotype (SH: 1.07 mm, SW: 1.02 mm) (MNHN-IM-2014-6401), South-Central Laos, Khammouan province, ca. 37 km ENE of Thakhek ( Muang Khammouan), ca. 4.5 km WNW of Mahaxai, on and under rocks in dry secondary forest under E exposed cliff, 150 m a.s.l., 17°25.956′N, 105°09.669′E (locality code: 3L07), coll. A. Abdou & I. V. Muratov, 25 November 2007 . Paratypes: 2 shells (MNHN-IM-2014-6402), same data as holotype; 3 shells (MNHN-IM-2014-6400), South-Central Laos, Khammouan province, ca. 10.5 km E of Thakhek ( Muang Khammouan), on and under rocks, cave deposits, in secondary forest under entrance and in large cave on NE exposed steep slope, 160 m a.s.l., 17°24.340′N, 104°54.894′E (locality code: 25L07), leg. A. Abdou & I. V. Muratov, 09 December 2007 ; 4 shells (MNHN-IM-2014-6399), South-Central Laos, Khammouan province, ca. 15 km NE of Thakhek ( Muang Khammouan), ca. 12.5 km SE of Ban Nase, on and under rocks in dry secondary forest near large flooded cave under W exposed cliff, 17°30.547′N, 104°53.444′E, alt. 127 m (locality code: 7L07), coll. A. Abdou & I. V. Muratov, 28 November 2007 .

Diagnosis. A Clostophis species with pointed apex. The toothless aperture might be the result of insufficient sampling or the species’ characteristics.

Description. Shell conical, slightly higher than wide, or in some specimens slightly wider than high. Apex pointed. Whorls rounded and very slightly shouldered. Tuba not detached from penultimate whorl. Protoconch consists of 1.25 whorls, pitted and spirally striated. Entire shell with 4 whorls. Umbilicus relatively narrow. Entire teleoconch with rather equidistant spiral striae, and some irregular radial growth lines of the same strength. Aperture subcircular, resembles that of juvenile specimens due to the lack of any teeth, and the sharp, not expanded peristome (see also Remarks). Aperture adnate to penultimate whorl.

Measurements (in mm). SH = 0.94–1.07, SW = 0.95–1.22 (n = 5).

Differential diagnosis. Shells of Clostophis infantilis , new species, can be distinguished from members of the genus Angustopila by the dense spiral striation of the shell. See under C. multiformis , new species.

Etymology. The specific epithet refers to the juvenile-looking shells of this species.

Remarks. Shells of Clostophis infantilis , new species, resemble juvenile shells of other Clostophis species due to the toothless aperture and the sharp, not expanded peristome. However, the shells of C. infantilis , new species, differ from all other Clostophis species in the region, and the relatively high number of available shells suggests that this species does not develop apertural barriers. Moreover, C. infantilis , new species, and C. multiformis , new species, occur sympatrically. Angustopila species also inhabit this area and have less dense spiral striae (unpublished information).

Figures

Fig. 5. Clostophis infantilis Páll-Gergely, new species (MNHN-IM-2014-6401, holotype). A, dorsal view; B, ventral view; C, apertural view; D, lateral view; E, protoconch sculpture; F, sculpture of the ventral side; G, sculpture of body whorl from standard apertural view