Clostophis obtusus Páll-Gergely & Grego, 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 : 364

Clostophis obtusus Páll-Gergely & Grego , new species

( Fig. 10 )

Material examined. Holotype (SH: 1.39 mm, SW: 1.22 mm) ( HNHM 104435 ), Laos, Khammouane Province, Tham Nam Dôn Cave, Earthquake Dome , sand sediments at bank of cave river, 160 m a.s.l., 17°33.815′N, 104°52.298′E (locality code: JG2B), coll. J. Grego, 11 February 2017 . Paratypes: 2 shells (coll. JG), same data as preceding; 1 shell (coll. JG), Laos, Khammouane Prov., 2 km WNW of Ban Na village, Pha Soung Cave – Frog lake, 17°33.054′N, 104°52.414′E (locality code: JG3A), leg. J. Grego, 09 February 2017 .

Diagnosis. A relatively large, triangular Clostophis species with blunt apex, a relatively narrow umbilicus, and a parietal tooth that is only slightly indicated.

Description. Shell conical, higher than wide. Whorls rounded and very slightly shouldered. Tuba not detached from penultimate whorl. Protoconch nearly reaches 1.75 whorls, pitted and spirally striated. Entire shell with 4.5 whorls. Umbilicus narrow. Entire teleoconch with rather equidistant spiral striae, and some weak, irregular radial growth lines. Aperture subcircular with straight parietal part. Parietal tooth very weak, only slightly indicted, but as long as in C. multiformis , new species. Aperture not adnate to penultimate whorl. Peristome expanded but not reflected.

Measurements (in mm). SH = 1.17–1.39, SW = 1.07–1.24 (n = 4).

Etymology. The specific epithet “ obtusus ” (= obtuse, blunt in Latin) refers to the blunt apex of this new species.

Differential diagnosis. Clostophis obtusus , new species, differs from C. multiformis , new species (populations northeast of Thakhek), in the following traits: the shell of C. obtusus is larger, always triangular, not ovoid, apex blunter, umbilicus narrower, aperture never detached from penultimate whorl, parietal tooth weaker.

Remarks. We first considered this species to be fitting into the wide variability of C. multiformis , new species, but in fact, at one site (locality: JG2B) the two species occur sympatrically.

Figures

Fig. 10. Clostophis obtusus Páll-Gergely & Grego, new species (HNHM 104435, holotype). A, ventral view; B, dorsal 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.