Paralaoma angusta Vermeulen, Liew & Schilthuizen

Vermeulen, Jaap J., Liew, Thor-Seng & Schilthuizen, Menno, 2015, Additions to the knowledge of the land snails of Sabah (Malaysia, Borneo), including 48 new species, ZooKeys 531, pp. 1-139 : 92

Taxon classification Animalia Stylommatophora Punctidae

Paralaoma angusta Vermeulen, Liew & Schilthuizen sp. n. Figure 76

Holotype. Malaysia, Sabah, West Coast Province , Crocker Range , Kiansom Waterfall ( RMNH.5003958 ).

Examined material from Sabah.

West Coast Province. Kiansom Waterfall in foothills of Crocker Range (leg. UMS Tropical Malacology Course, 2005, V 12736).

Description.

Shell minute, thin, slightly translucent, yellowish brown, low-conical to lenticular, apex rounded. Surface shiny. Whorls well-rounded. Protoconch sculpture: densely placed radial riblets which are particularly distinct towards the periphery; fine, rather densely placed spiral grooves cutting into the crests of the radial riblets. Teleoconch, radial sculpture: locally distinct, widely spaced radial ribs, often with a periostracal crest, which gradually disappear towards the umbilicus; in between these very fine, densely placed, low secondary riblets above the periphery. Spiral sculpture teleochonch: spiral threads, as fine and as densely placed as the secondary radial riblets, above the periphery, grading into widely spaced, rather distinct grooves towards the umbilicus. Umbilicus narrow, 5-6 % of the shell width. Dimensions: height up to 1.1 mm; width up to 1,6 mm; diameter of the first three whorls 0.40-0.45 mm, 0.75-0.80 mm, 1.25-1.30 mm respectively; number of whorls up to 3 3/4, height aperture up to 0.75 mm; width aperture up to 0.90 mm.

Habitat in Sabah and distribution.

Secondary forest on sandstone hills, lowland conditions. Sabah: West Coast, one locality known. Endemic to Sabah.

Cross diagnosis.

Characterized within the genus by the narrow umbilicus, the presence of radial riblets on the protoconch, and the distinct and widely spaced spiral sculpture on the lower surface.

Etymology.

The name refers the the narrow umbilicus [angustus (L.) = narrow].