Perrottetia dugasti (Morlet, 1892)

Inkhavilay, Khamla, Siriboon, Thanit, Sutcharit, Chirasak, Rowson, Ben & Panha, Somsak, 2016, The first revision of the carnivorous land snail family Streptaxidae in Laos, with description of three new species (Pulmonata, Stylommatophora, Streptaxidae), ZooKeys 589, pp. 23-53 : 35

Taxon classification Animalia Pulmonata Streptaxidae

Perrottetia dugasti (Morlet, 1892) Fig. 5A

Streptaxis dugasti Morlet 1892: 82. Morlet 1893 [ 1892]: 315, 316, pl. 7, fig. 5, 5a, 5b. Type locality: Laï-Chau, sur les bords de la Riviére Noire, Tonkin [on the banks of the Black River, Lai Chau Province, Vietnam]. Gude 1903: 255.

Perrottetia dugasti - Kobelt 1906: 123, 124, pl. 61, fig. 13. Richardson 1988: 239. Schileyko 2011: 23.

Material examined.

The species was described based on material from L. Dugast collection but no illustration was given. Morlet (1893: 315, 316, pl. 7, fig. 5, 5a, 5b) subsequently published the description and illustrated a single specimen. There is a specimen of L. Morlet in the MNHN collections with an original label stating “Type”. In order to stabilise the name, the shell that closely matched with the measurements given in the original description and illustration in Morlet (1893: pl. 7, fig. 5, 5a, 5b) is here designated as lectotype MNHN-IM 200030867 (Fig. 4A).

Remarks.

Shell sub-oblique heliciform with depressed spire and 6 whorls. Shell surface smooth, glossy and with a distinct suture. Embryonic shell smooth, following whorl regularly expanded. Last whorl rounded, axially deflected, with longitudinal furrows present. Aperture narrow; peristome discontinuous, thick and expanded, and short sinulus present. Aperture dentition consisting of two parietal lamellae (lower one large; upper one small and close to sinulus), one palatal lamella, one basal lamella and one bifid columellar lamella.

Compared with Perrottetia messageri (Bavay & Dautzenberg, 1908), this species differs in having a strong lower parietal lamella, a bifid columellar lamella, and the left periphery of penultimate whorl not extended beyond the diameter of the last whorl. In contrast, Perrottetia messageri has a strong columellar lamella, a supracolumellar lamella is present, and the left periphery of the penultimate whorl extended beyond the diameter of the last whorl (Fig. 5D).