Pincerna clausa, Sang & Son, 2022

Sang, Do Duc & Son, Nguyen Thanh, 2022, The land snail genus Pincerna Preston, 1907 (Gastropoda: Alycaeidae) from Vietnam and Laos, with description of a new species, Raffles Bulletin of Zoology 70, pp. 364-375 : 372-373

publication ID

https://doi.org/ 10.26107/RBZ-2022-0018

publication LSID

lsid:zoobank.org:pub:E3A5AA23-BEAE-445E-981F-93A9E7A79417

persistent identifier

https://treatment.plazi.org/id/03A68780-FFCC-FFA5-8D6C-07FE7CF4110E

treatment provided by

Felipe

scientific name

Pincerna clausa
status

sp. nov.

Pincerna clausa View in CoL , new species

( Figs. 1 View Fig , 4A–C View Fig , 5A–F View Fig , 6D View Fig ; Tables 1, 2)

Type material. Holotype (1 shell, height 5.2 mm, width 5.0 mm; Figs. 4A View Fig , 6D View Fig ) ( VNMN-IZ 002.304 ), Vietnam, Điện Biên Province , Điện Biên District, Na Ư Commune, near Tây Trang international border gate at the Vietnam - Laos border region, exposed limestone with little soil and vegetation of herbs, 814 m a.s.l., 21°13′34″N, 102°58′3″E, col. D.S. Do & C. Vilachark, 08 December 2018 GoogleMaps ; Paratypes: 3 paratypes ( ZMHU. MOL 044 ), same data as holotype GoogleMaps .

Etymology. This new species is named for its conspicuous closed umbilicus (Latin: clausa = close).

Diagnosis. Pincerna clausa , new species, is characterised by a small sized, globular shell with clearly spiral striation on R1 and a closed umbilicus, which is completely obscured by the reflected columellar extension.

Description. Shell globose, off-white, rather glossy, medium sized (height 5.1–5.3 mm, width 4.9–5.0 mm). Spire high, slightly obtuse (spire height 1.3–1.4, spire width 1.8–2.0 mm). Whorls 4.25–4.5, the periphery rounded. Suture rather deep. Protoconch smooth, glossy, without spiral striation, 1.25–1.75 whorls. R1 of 2.0 whorls, with rather regular, indistinct and low ribs, and clearly spiral striation; on the first part of R1 the ribs are rather weak and irregular, on the last part, however, they are close together and sharp, with well visible spiral striation ( Figs. 4 View Fig , 6D View Fig ). R1 and R2 boundary conspicuous due to denser and slender R2 ribs. R2 and breathing tube relatively long (breathing tube length ca 1.2–1.4 mm), consisting of 34–41 stripes, which are slender and slightly elevated from the surface, overall surface slightly wrinkled. R3 slightly longer than R2; boundary between R2 and R3 distinct due to constriction and change in sculpture. R3 smooth, glossy, with some widely spaced, irregular and weak ribs on the terminal part. Aperture circular, moderately expanded (aperture diameter 3.0–3.1 mm). Peristome double, slightly thickened; outer peristome sharp, expanded but not reflected; inner peristome protruding, sharp; outer and inner peristomes are clearly separated. Umbilicus narrow and completely obscured by the reflected columellar extension.

Operculum. Unknown.

Distribution. The new species is thus far known only from the limestone hill in Na Ư Commune, Điện Biên District, Điện Biên Province, northwest Vietnam ( Fig. 1 View Fig ).

Remarks. This new species has a similar shell shape as Pincerna vanbuensis but differs in having a closed umbilicus, stronger spiral striation on R1, and weaker ribs on R2. Pincerna clausa , new species, also resembles Pincerna costulusus in shell shape but differs in its more pronounced spiral striation as well as R1 with denser and weaker ribs. It differs from Pincerna anceyi by having much stronger, more widely-spaced ribs, well visible spiral striation and closed umbilicus. It differs from P. mouhoti by having a narrow umbilicus and smaller shell size.

ZMHU

Zoologisches Museum der Humboldt Universitaet

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