Haploptychius blaisei (Dautzenberg & Fischer, 1905)

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 : 32-33

Taxon classification Animalia Pulmonata Streptaxidae

Haploptychius blaisei (Dautzenberg & Fischer, 1905) Figs 1, 4 D–F; Table 1

Streptaxis blaisei Dautzenberg and Fischer 1905: 86, 87, pl. 3, figs 1-4. Type locality: Ile Krieu, Tonkin [Krieu Island, Ha Long, Quang Ninh Province, Vietnam].

Haploptychius blaisei - Kobelt 1906: 173, pl. 66, figs 4-7. Richardson 1988: 212.

Material examined.

The original description was based on single specimen since stated "un seul examplaire" (a single example). The specimen of M. Blaise in the MNHN collections is considered as holotype MNHN-IM 200030866 (Fig. 4D).

Phu Ly, Dongson, Ha Nam, Vietnam: NHMUK Vermeulen coll. (4 shells). Tam Phatok, Ngoi, Luang Phrabang, Laos: CUMZ 6276 (1 shell; Fig. 4E), 6257 (15 shells; Fig. 4F).

Remarks.

Shell oblique-heliciform, white and translucent. Whorls 6½; spire depressed to slightly convex, with distinct suture. Shell surface glossy, with thin transverse ridges that diminish below periphery and around umbilicus. Embryonic shell large, about 2½ whorls, with a smooth surface; following whorls regularly expanded. Penultimate whorl rounded; last whorl axially deflected. Aperture semi-ovate; peristome discontinuous, parietal callus thin; lip thickened and slightly expanded. Apertural dentition with one strong parietal lamella. Umbilicus widely open and shallow.

Haploptychius blaisei is superficially similar to Haploptychius diespiter (Mabille, 1887) and Haploptychius dorri from north Vietnam, but it has a larger shell, more depressed spire, rounded penultimate whorl, a wide and deep umbilicus, and thin transverse ridges on the upper periphery. For comparison, Haploptychius diespiter (Fig. 4B) has the last whorl less deviated from the vertical axis, and Haploptychius dorri (Fig. 4C) has a more depressed suture.