Geotrochus scolops 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 : 107-108

Taxon classification Animalia Stylommatophora Trochomorphidae

Geotrochus scolops Vermeulen, Liew & Schilthuizen sp. n. Figure 88

Holotype. Malaysia, Sabah, Tawau Province , Tawau Hills N.P. (leg. J.P. King, BOR/MOL 2432 ) .

Description.

Shell medium-sized, rather thin, about opaque, brown, above the periphery with a very fine, slightly paler spiral striation, high-conical with concave sides; apex protruding. Surface slightly shiny above the periphery, glossy below. Whorls: Apical whorls moderately convex, other whorls slightly convex, slightly shouldered, last whorl almost flat; suture impressed in the inner whorls, not so in the outer, coinciding with the periphery; last whorl acutely angular, slightly compressed at the periphery, slightly rounded below the periphery. Protoconch c. 2 whorls, smooth. Teleoconch. Radial sculpture: above the periphery growth lines, slightly raised locally; below the periphery indistinct growth lines only. Spiral sculpture: last whorl with a sharp, somewhat pinched peripheral keel; start of fifth whorl with c. 3 thin, low, widely spaced spiral threads with an irregularly incised crest: 1 slightly more distinct close to the periphery, as well as 2 inconspicuous above these (penultimate whorl with c. 8 such threads, of which 3-4 are slightly more distinct); no spiral sculpture below the periphery. Umbilicus closed. Peristome slightly thickenened, but not reflexed except on the columellar side. Dimensions: Height c. 10.4 mm; width c. 12.5 mm; h/w 0.83-0.84; diameters of the first 4 whorls c. 1.1 mm, c. 1.7 mm, c. 2.2 mm, c. 3.0 mm respectively; number of whorls c. 8 3/8, height aperture c. 3 mm; width aperture c. 6.5 mm.

Habitat in Sabah and distribution.

Forest on sandstone or volcanic soil, lowland conditions. Sabah: Tawau Hills National Park. Endemic to Sabah.

Cross diagnosis.

Uniquely identified within Geotrochus by the high-conical shell with concave sides, and tapering towards the apex.

Geotrochus conicoides with a relatively high-conical shell are most similar, but still have a lower h/w-ratio: 0.57-0.66.

Etymology.

The name refers to the shape of the spire [scolops (Gr.) = pointed].