Clostophis multiformis Páll-Gergely & A. Reischütz, 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 : 358-363

Clostophis multiformis Páll-Gergely & A. Reischütz , new species

( Figs. 7–9 )

Type material. Holotype (SH: 1.09 mm, SW: 1.03 mm) ( NHMW 113273 , Fig. 7 ), Laos, Khammouane Prov., limestone hill in rice fields east of the road 1E, 300 m SE Gnommalat, NE Thakhek , at the base of rocks, 17°36.064′N, 105°10.356′E (locality code: La.4), coll. A. Reischütz, March 2010 . Paratypes: 1 shell ( NHMW 113274 , Fig. 8 ), Laos, Khammouane Prov., limestone hill at the Xe Bangfai river city bridge from Mahaxay, E Thakhek , 17°24.608′N, 105°12.119′E (locality code: La. 8), coll. A. Reischütz, March 2010 ; 2 shells (coll. RE), same data as preceding; 1 shell (coll. SA), Laos, Khammouane Province, 2 km N of Gnommalath , in dry soil on rock at foot of limestone hill, near the weir of powerplant channel, 17°34.859′N, 105°10.091′E (locality code: SA1 ), coll. S. Aiken, 19 July 2019 ; 3 shells (MNHN-IM-2014-6404), 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 ; 1 shell (MNHN-IM-2014-6403), South-Central Laos, Khammouan province, ca. 35 km ENE of Thakhek ( Muang Khammouan), ca. 7 km WNW of Mahaxai, on and under rocks in dry secondary forest under S exposed cliff, 169 m a.s.l., 17°26.736′N, 105°08.360′E (locality code: 4L07), coll. A. Abdou & I. V. Muratov, 25 November 2007 .

Additional material. 2 shells (coll. JG), 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 ; 1 shell ( HNHM 104434 , Fig. 9 ), Laos, Khammouane Province, cave at the NE foot of Mt. Pha Soung , caverns among slope boulders, 153 m a.sl., 17°33.108′N, 104°52.301′E (locality code: JG4 ), coll. J. Grego, 08 February 2017 ; 2 shells (coll. JG), same data as preceding; 3 shells (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), coll. Grego, J., 09 February 2017 .

Diagnosis. This variable Clostophis species is characterised by a conical or ovoid-conical shell, a constricted, teardrop- or kidney-shaped aperture with a weak parietal tooth, and a rather wide umbilicus.

Description. Shell conical or ovoid, higher than wide to wider than high. Whorls rounded or very slightly shouldered. Tuba slightly (usually) or strongly (rarely) detached from penultimate whorl. Protoconch consisting of 1.25–1.5 whorls, pitted and spirally striated. Entire shell with 4.25–4.5 whorls. Umbilicus wide, occupies ca. one third of the shell width (see also Remarks). Entire teleoconch with strong, elevated, rather equidistant spiral striae (see also Remarks), and some weak, irregular radial growth lines. Aperture teardrop- or kidney-shaped. Sinulus wide. Parietal tooth weak and relatively short, in some shells reaches, in others does not reach peristome. In some shells there is a slight indication of a palatal tooth. Peristome expanded but not reflected.

Measurements (in mm). SH = 1.02–1.4, SW = 1.03–1.39 (n = 11, shells belonging to multiple populations).

Differential diagnosis. Clostophis infantilis , new species, has a smaller shell, a more pointed apex, stronger radial sculptural elements, and a narrower umbilicus. See also under C. obtusus , new species.

Etymology. This new species is named after the variability of its shell shape across populations.

Remarks. This is a variable species in terms of shape and size, and the density of spiral striae. Future investigations including more detailed sampling and larger sample sizes might reveal that the populations listed here belong to multiple species. The populations east of Thakhek (localities: 3L07, 4L07, La.4, La.8, SA1) are slightly smaller (SH: 1.09–1.21 mm, SW: 1.03–1.12 mm vs. SH: 1.14–1.4 mm, SW: 1.21– 1.39 mm) and have a higher spire and a narrower umbilicus than the populations northeast of Thakhek (localities: JG2B, JG3A, JG4). The sculpture and the aperture dentition of the two groups are similar. We have no samples from the area between the two known areas, therefore, at the moment, we see no necessity of splitting this species into subspecies. The tube (terminal part of the body whorl) is slightly detached from the penultimate whorl, but in one population (locality: La.8) it was strongly detached. Nearly all examined shells have dense spiral striation (26–30 striae counted in the middle line of the body whorl from standard apertural view), whereas the single shell from population JG4 has only 20 striae. The shell and aperture shape are similar to the neighbouring population (locality: JG3A) and therefore, we consider it conspecific with the neighbouring population (locality: JG4). See Fig. 2 .

Figures

Fig. 7. Clostophis multiformis Páll-Gergely & A. Reischütz, new species (NHMW 113273, holotype). A, dorsal view; B, ventral view; C, apertural view; D, lateral view; E, aperture dentition; F, protoconch sculpture; G, sculpture of the ventral side; H, sculpture of body whorl from standard apertural view.

Fig. 8. Clostophis multiformis Páll-Gergely & A. Reischütz, new species (NHMW 113274, paratype). A, dorsal view; B, ventral view; C, apertural view; D, lateral view; E, aperture dentition; F, protoconch sculpture; G, sculpture of the ventral side; H, sculpture of body whorl from standard apertural view.

Fig. 9. Clostophis multiformis Páll-Gergely & A. Reischütz, new species (HNHM 104434, JG4). A, lateral view; B, ventral view; C, apertural view; D, dorsal view; E, protoconch sculpture; F, aperture dentition; G, sculpture of the ventral side; H, sculpture of body whorl from standard apertural view.

Fig. 2. Known distribution of Clostophis species. Empty triangle: Clostophis stochi; inverted empty triangle: C. proboscideus; filled triangle: Clostophis sankeyi; inverted filled triangle: Clostophis koilobasis, new species, and Clostophis incurvus, new species; filled square: Clostophis neglectus; filled diamond: Clostophis platytrochus, new species. Inset map shows the distribution of Clostophis multiformis, new species (circles with labels, see explanation in the text), Clostophis obtusus, new species (empty diamond), and Clostophis infantilis, new species (empty square), east of Thakhek.