Taxon classification Animalia Stylommatophora Plectopylidae

Gudeodiscus (Veludiscus) emigrans (Moellendorff, 1901)

Diagnosis.

A medium-sized to large species with dense, fine riblets; shell flat, callus always, apertural fold usually present. Parietal wall with C-shaped posterior lamella; anterior lamella (if present) slightly S-shaped; if anterior lamella is missing; one lower plica or four parallel plicae are visible in front of the lamella; palatal wall with almost straight, slightly oblique, depressed Z-shaped or Y-shaped plicae (Figures 13 A–D).

Differential diagnosis.

Gudeodiscus phlyarius has stronger apertural fold, a straight anterior parietal lamella (in the Chinese populations assigned to Gudeodiscus phlyarius werneri Páll-Gergely, 2013 = synonym of phlyarius, sometimes dissolved into small denticles) and usually a somewhat elevated spire. Gudeodiscus messageri, Gudeodiscus hemmeni sp. n. and Gudeodiscus anceyi have two parietal lamellae or several small denticles standing in a line at the position of the first lamella.

General distribution.

The three subspecies of Gudeodiscus emigrans are known from northern Vietnam and northern Guangxi.