Discartemon plussensis (Morgan, 1885)

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 : 64

11. Discartemon plussensis (Morgan, 1885) Figs 6A, B, 23, Table 2

Streptaxis plussensis Morgan, 1885a [Jan.]: 68. Type locality: Mont Tchéhèl, dans la Vallée de la rivière Pluss. Morgan 1885b [Aug.]: 371, 372, pl. 5, fig. 1. Tryon 1885: 251. Möllendorff 1887: 299, 300. Tenison-Woods 1888: 1009. Möllendorff 1891: 330, 331. Gude 1903: 226.

Odontartemon (Discartemon) plussensis - Kobelt 1906: 99, pl. 54, figs 12-14. Kobelt 1910: 150.

Discartemon plussensis - Benthem Jutting 1954: 79, fig. 2. Benthem Jutting 1959: 168. Richardson 1988: 184. Maassen 2001: 87, 88.

Material examined.

Perak, Malaysia NHMUK 1939.4.13.22 (1 shell; Fig. 6A). Sungei Siput, Perak, Malaysia: NMW 1955.158.25253 (13 shells). RMNH Kaumans Reg. 598 (3 shells). Hot Springs, Tanjung Rambutan, Perak, Mlaysia: RMNH Drijver Coll. (1 shell). Yan Tao San, Perak, Malaysia: CUMZ 6008. Ipoh, Perak, Malaysia (4°36'34.6"N, 101°6'49.9"E): CUMZ 6009 (Fig. 6B; 3 shells).

Remarks.

The original descriptions included informative figures ( Morgan 1885a, b), and subsequently Benthem Jutting (1954: fig. 2) published excellent figures of topotype specimens. These allow unambiguous recognition of this species. Shell depressed-heliciform with a flattened spire. Shell surface with transverse ridges that diminish below periphery and varices present; following whorls regularly coiled. Last whorl rounded and regularly expanded; umbilicus widely open and deep. Aperture triangular with sinulus, and apertural dentition with one parietal and one palatal lamella (Fig. 6B).

Compared with Discartemon leptoglyphus and Discartemon plussensis , it differs in its smaller shell, with transverse ridges that diminish below periphery, last whorl rounded and more inflated, and sinulus present.