Pincerna Preston 1907

Genus Pincerna Preston, 1907

Pincerna Preston, 1907: 206. (introduced as a subgenus of Alycaeus, but apparently used on genus level).

Alycaeus (Cycloryx) Godwin-Austen, 1914: 334. New synonym

Type species. Pincerna liratula Preston, 1907, by monotypy. Alycaeus thieroti Morgan, 1885 (Type locality: “G. Lano” near Perak) is very similar to Pincerna liratula (“Ke-lantan” in the Malay Peninsula); the latter might be a junior synonym of the former.

Remarks. The genus-level revision of the family Alycaeidae is in progress and beyond the scope of the present paper. However, to place the new species in a genus correctly, some information on the relationship of the genus Cycloryx Godwin-Austen, 1914, and Pincerna Preston, 1907, must be added.

The discovery of Pincerna yanseni n. sp. is surprising because it shows only superficial similarity with most other Alycaeidae of the Malay Archipelago, but it is similar to many species from northeastern India and Myanmar classified in the genus Cycloryx. The genus Cycloryx (type species: Alycaeus constrictus Benson, 1851 by original designation, Fig. 1A) was erected as a subgenus of Alycaeus Baird, 1850, and was diagnosed on the basis of the ovately conoid shell shape, the regular ribbing on the upper whorls, and the extremely short, often clubbed or pear-shaped sutural tube (Godwin-Austen, 1914). Godwin-Austen (1914) only included species from northeastern India and Burma (Rakhin = Arakan, and the Shan States). However, the diagnosis of Cycloryx matches several species extralimital to the distributional range as defined by Godwin-Austen: Alycaeus costulosus Bavay & Dautzenberg, 1912 (northern Vietnam), Alycaeus globosus H. Adams, 1870 and its subspecies (Borneo), Dioryx maolanensis Luo et al., 2009 (Guizhou, China), Alycaeus thieroti Morgan, 1885 (Perak, Malay Peninsula), and Pincerna liratula Preston, 1907 (Malay Peninsula and Sumatra). Some populations of the latter species have a slightly longer tube than the other species, but have the typical rather globular shell shape with strong radial sculpture.

Originally, the subgenus Pincerna was diagnosed on the basis of a “circular cup” on the outer surface of the operculum. The outer surface of operculum, however, has limited taxonomic value on the genus level in the Alycaeidae, especially that outer rings have been developed in multiple alycaeid genera (Páll-Gergely et al., in press). Consequently, no important shell characters distinguish Cycloryx and Pincerna, and they should be synonymised. Because Pincerna has been introduced earlier, Cycloryx is a junior synonym.