Discartemon sykesi (Collinge, 1902)

Siriboon, Thanit, Sutcharit, Chirasak, Naggs, Fred, Rowson, Ben & Panha, Somsak, 2014, Revision of the carnivorous snail genus Discartemon Pfeiffer, 1856, with description of twelve new species (Pulmonata, Streptaxidae), ZooKeys 401, pp. 45-107 : 55

3. Discartemon sykesi (Collinge, 1902) Figs 4E, F, 23

Streptaxis sykesi Collinge, 1902: 72, pl. 4, figs 1, 2. Type locality: Biserat, State of Jalor. Laidlaw 1933: 233.

Odontartemon (Discartemon) sykesi - Kobelt 1906: 100, pl. 55, figs 1, 2. Kobelt 1910: 150.

Discartemon sykesi - Benthem Jutting 1954: 86, 87. Benthem Jutting 1959: 168. Richardson 1988: 184, 185. Maassen 2001: 88, 89. Hemmen and Hemmen 2001: 42.

Material examined.

Paratypes NHMUK 1937.7.9.11 (1 shell; Fig. 4F) and NMW 1955.158.25257 (1 shell; Fig. 4E).

Remarks.

The distinguishing characters of this species are the flattened shell and spire with a distinct suture. Shell surface nearly smooth with thin growth lines, varices present; following whorls regularly coiled. Last whorl angular, intermediately expanded; umbilicus very wide and showing all preceding whorls. Aperture semi-ovate with sinulus; peristome thickened, expanded and reflected; apertural dentition with only one parietal lamella (Fig. 4E).

Discartemon sykesi differs from Discartemon discus in its smaller shell, in the presence of a sinulus, the intermediately expanded last whorl, and in being restricted to the Malay Peninsula. This species can be distinguished from Discartemon planus in having a larger shell with flattened spire, the last whorl angular and intermediately expanded, a semi-ovate aperture, and in lacking palatal and columellar lamellae.