Plectostoma whitteni, Liew, Thor-Seng, Vermeulen, Jaap Jan, Marzuki, Mohammad Effendi bin & Schilthuizen, Menno, 2014

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 : 42-43

Plectostoma whitteni sp. n. Figures 17G, 28, Appendix 8

Type material.

Holotype: BOR 5644(1). Paratypes: BOR 5536(>10), V 8802(1), V 8885(>10).

Diagnosis.

Shares with Plectostoma tonkinianum the general shell form, in the terms of apex, spire and tuba, but differs by lacking constriction teeth and lower spire (<2 mm).

Etymology.

This species is named after Dr. Tony Whitten, who was senior biodiversity specialist of the World Bank between 1995 and 2010, and is currently the Regional Director for Asia-Pacific Fauna & Flora International. Dr. Whitten has been actively promoting the protection of the biodiversity that is associated with limestone and has been involved in conservation action to protect limestone habitats.

Description.

Apex. Shape: distinctly convex.

Spire. Height: 1.7-1.9 mm. Width: 1.4-1.6 mm. Number of whorls: 3 7/8-4 1/4. Apical spire shape: depressed conical. Basal spire shape: ovoid. Whorl periphery: distinctly convex. Umbilicus: completely closed by tuba.

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

Tuba. Coiling direction: type 3 and aperture visible in left lateral view. Tuba whorl length in proportion to spire last whorl: ca. 1/2-5/8. 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: absent. Thin lines: present.

Radial ribs. Rib density: 6-7 ribs per mm. Rib intensity: thin. Shape: straight. Inclination: orthoclin.

Distribution.

Type locality. Gua Taat, Tasik Kenyir (4°51'3"N, 102°43'21"E).

Distribution range. This species only occurs in Gua Taat, Tasik Kenyir (Figure 18A).

Conservation status.

Least Concern. Gua Taat is located in a prioritised protected National Park with good forest cover.

Discussion.

The general shell form of Plectostoma whitteni is similar to Plectostoma tonkinianum . There is no genetic information for Plectostoma tonkinianum , but Plectostoma whitteni is genetically closer to Plectostoma tohchinyawi than to any of the other 18 species. Nevertheless, Plectostoma whitteni is considered a distinct species as compared to Plectostoma tonkinianum and Plectostoma tohchinyawi because of the lack of constriction teeth.