Pincerna Preston, 1907

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 : 365

Genus Pincerna Preston, 1907

Alycaeus (Pincerna) Preston, 1907: 206 . Type species: Alycaeus

(Pincerna) liratula Preston, 1907, by monotypy. Alycaeus (Cycloryx) Godwin-Austen, 1914: 334 . Chamalycaeus (Cyclory x) – Thiele, 1929: 108; Wenz, 1938: 478. Alycaeus (Pincerna) – Thiele, 1929: 108; Wenz, 1938: 479;

Egorov, 2013: 33. Chamalycaeus (Cycloryx) – Egorov, 2013: 36. Pincerna – Páll-Gergely, 2017: 214; Páll-Gergely et al., 2017: 10;

2020: 167; Vermeulen & Liew, 2022: 27.

Diagnosis. Shell globose to conical, usually translucent; whorls 3½–5, increase regularly; protoconch glossy, smooth, 1–1¾ whorls; R1 usually with strong, regularly spaced ribs and weak spiral striation; R2 smooth to prominently ribbed, usually short, with slender, relatively dense and regular ribs; umbilicus narrow and often closed by the reflected columellar extension of peristome; Operculum thin, translucent, usually flat on both the outer and inner surfaces ( Egorov, 2013; Páll-Gergely, 2017; Páll-Gergely et al., 2020; Vermeulen & Liew, 2022: 27).

Distribution. The genus Pincerna is widely distributed in Asia from the southeastern Himalayas to Laos, Vietnam, the Malay Peninsula, Sumatra, and northern Borneo (PállGergely et al., 2020; Vermeulen & Liew, 2022).

Remarks. Pincerna is probably most closely related to Stomacosmethis , which is similar in shell size and shape (Páll-Gergely et al., 2020). The shells of Pincerna species are all globular, with more widely spaced ribs on R1, not colourful, mostly white and translucent, thin operculum, which is relatively flat on both the outer and inner surface. In contrast, the shells of Stomacosmethis species are triangular with densely ribbed on R1, extremely short R2, usually brightly coloured yellow or orange, thin operculum with outer surface usually elevated ( Foon & Liew, 2017; PállGergely et al., 2020).