Plectostoma panhai (Maassen, 2001)

Liew, Thor-Seng, Vermeulen, Jaap Jan, Marzuki, Mohammad Effendi bin & Schilthuizen, Menno, 2014, A cybertaxonomic revision of the micro-landsnail genus Plectostoma Adam (Mollusca, Caenogastropoda, Diplommatinidae), from Peninsular Malaysia, Sumatra and Indochina, ZooKeys 393, pp. 1-107 : 35-36

Plectostoma panhai (Maassen, 2001) Figure 24, Appendix 7

Arinia panhai Maassen, 2001: 55, figure 4, 12 & 13 (original description).

Type material.

Holotype: RMNH 81809(1) (Seen). Paratypes: RMNH 81810(2) (Seen).

Other examined materials.

ZMA 138438(1).

Diagnosis.

Shares with Plectostoma mengaburensis and Plectostoma dindingensis the general shell form, in the terms of apex, spire and tuba, but differs by having a single parietal constriction tooth.

Description.

Apex. Shape: moderately convex.

Spire. Height: 2.1-2.2 mm. Width: 1.6-1.7 mm. Number of whorls: 4 1/2-4 5/8. Apical spire shape: depressed conical. Basal spire shape: ovoid. Whorl periphery: moderately convex. Umbilicus: open.

Constriction. Parietal teeth: one. Basal teeth: none.

Tuba. Coiling direction: type 1 and aperture visible from back view. Tuba whorl length in proportion to spire last whorl: ca. 3/4. Proportion of tuba that attaches to spire: whole.

Aperture and peristome. Peristome: double peristomes. Outer peristome shape: same as inner peristome and uniformly projected all around, except the posterior part.

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

Radial ribs. Rib density: 8-9 ribs per mm. Rib intensity: thin. Shape: straight. Inclination: orthoclin.

Distribution.

Type locality. Tham Krachaeng, Thailand (6°12'50"N, 101°12'9"E). The location description in the original publication is not completely correct "(06°55'022"N, 101°12'160"E)" ( Maassen 2001).

Distribution range. This species is only known from the type locality (Figure 18D).

Conservation status.

Data Deficient.

Discussion.

See discussion under Plectostoma christae .