Plectostoma tenggekensis sp. n. Figure 47, Appendix 14

Type material.

Holotype: BOR 5650(1). Paratypes: V 13554(5), BOR 444(4), BOR 5596(>10).

Diagnosis.

Shares with Plectostoma laidlawi, Plectostoma annandalei, and Plectostoma praeco the general shell from, in terms of spire and tuba shape, but differs by having single-humped shaped ribs.

Etymology .

This species is named after its type locality–Bukit Tenggek, Kuantan, Pahang.

Description.

Apex. Shape: moderately convex.

Spire. Height: 1.6-1.7 mm. Width: 1.3-1.4 mm. Number of whorls: 4-4 1/4. Apical spire shape: depressed. Basal spire shape: conical. Whorl periphery: moderately convex. Umbilicus: open.

Constriction. Parietal teeth: two. Basal teeth: none.

Tuba. Coiling direction: type 2 and aperture visible in right lateral view. Tuba whorl length in proportion to spire last whorl: ca. 5/8 of the spire last whorl length. Proportion of tuba that attaches to spire: less than 1/3.

Aperture and peristome. Peristome: double peristomes. Outer peristome shape: similar to inner peristome, projected all around, except the posterior part, where the left lateral sides are slightly more projected than the anterior and right lateral side.

Spiral lines. Thick lines: absent. Thin lines: present.

Radial ribs. Rib density: 6-7 ribs per mm. Rib intensity: thin. Shape: slightly curved. Inclination: moderately prosoclin.

Distribution.

Type locality. Bukit Tenggek, Pahang (4°0'51"N, 103°9'34"E).

Distribution range. Endemic to type locality (Figure 18B).

Conservation status.

Critically Endangered (B2ab(iii)+C2a(i) ver. 10.1). The entire Bukit Tenggek will be gone by 2014 because of quarrying activity.

Discussion.

See discussion under Plectostoma praeco .