Indoartemon diodonta Inkhavilay & Panha

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 : 40-43

Taxon classification Animalia Pulmonata Streptaxidae

Indoartemon diodonta Inkhavilay & Panha sp. n. Figs 1, 6 D–F; Table 1

Type material.

Holotype CUMZ 6289 (Fig. 6D). Measurement: shell height 7.5 mm, shell width 8.3 mm, and with 7 whorls. Paratypes: CUMZ 6290 (44 shells; Fig. 6E), NHMUK 20160252 (2 shells), NUOL (2 shells), SMF (2 shells).

Other material examined.

Tam Nang Ann, Tha Khek, Khammouan, Laos: CUMZ 6291 (7 shells, Fig. 6F). Tam Xieng Lieb, Tha Khek, Khammouan, Laos: CUMZ 6292 (15 shells).

Type locality.

Tam Xang, Tha Khek, Khammouan, Laos, 17°25'44.0"N, 104°51'49.1"E.

Diagnosis.

This new species superficially resembles Indoartemon eburneus and Indoartemon prestoni from Thailand, but it differs in having a much smaller shell, an oblique-heliciform shape, open umbilicus, and the last whorl is strongly deviated from the vertical axis. This species differs from Indoartemon medius from Thailand in its smaller shells, angular penultimate whorl and thin transverse ridges. Indoartemon diodonta sp. n. differs from Indoartemon bidens ( Möllendorff, 1883) from Hainan and Indoartemon tridens by having fine transverse ridges on the upper periphery, and the last whorl is less deviated from the vertical axis. These two species also have a smooth shell surface and a more strongly deviated last whorl, and a bifid columellar lamella is present in Indoartemon tridens .

Description.

Shell. Shell oblique-heliciform, white and translucent; whorls 6½– 7, spire conical, with distinct suture. Shell surface dull, with fine transverse ridges that diminish below the periphery. Embryonic shell large, about 2½ whorls, with smooth surface; following whorls regularly coiled. Last whorl shouldered, axially deflected, and not expanded. Aperture subcircular; peristome continuous, parietal callus thickened; lip thickened, expanded and little reflected. Apertural dentition with one large and strong parietal and one small palatal lamellae. Umbilicus narrow and deep (Fig. 6 D–F).

Etymology.

The specific epithet “diodonta” is derived from the Greek words “di” meaning “two” and “odontos” meaning “tooth”, referring to the dentition of the new species.

Distribution.

This species is known from limestone karst in Khammouan Province, central Laos. The animals can be found at altitudes up to 140 meters above mean sea level.

Remarks.

To date no living specimens have been collected.