Geotrochus spilokeiria 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 : 106-107

Taxon classification Animalia Stylommatophora Trochomorphidae

Geotrochus spilokeiria Vermeulen, Liew & Schilthuizen sp. n. Figure 87

Holotype.

Malaysia, Sabah, West Coast Province, Crocker Range N.P., Ulu Kimanis, along Keningau-Kimanis road (BOR/MOL 2784).

Description.

Shell medium-sized, rather thin, opaque, above the periphery greyish with a somewhat vaguely outlined brown band just above the peripheral keel, and with an irregular pattern of white stains and spots which more or less follow the radial and spiral sculpture, periphery white, below the periphery dark brown, grading to white towards the periphery; shell conical with convex sides; apex not protruding. Surface shiny above the periphery, glossy below. Whorls: Apical whorls moderately convex, next whorls slightly convex, slightly shouldered, outer whorl almost flat; suture somewhat impressed in the apical whorls, not so in the outer whorls, coinciding with the periphery; last whorl acutely angular, slightly compressed at the periphery, slightly rounded below the periphery. Protoconch c. 1 5/8 whorls, smooth. Teleoconch. Radial sculpture: above the periphery rather distinct growth lines, raised at irregular intervals; below the periphery indistinct growth lines only. Spiral sculpture: last whorl with a sharp, pinched peripheral keel; above and close to this keel 1 thin, low, sharply outline spiral thread; above this 3-4 very low and wide, vaguely outlined ridges locally visible in tangential light; next to this radial and spiral sculpture oblique rows of very shallow, vaguely outlined indentations are locally visible; below the periphery locally with traces of a fine, shallow, vaguely outlined spiral striation. Umbilicus closed. Peristome not thickened, nor reflexed except on the columellar side (see remarks below). Dimensions: Height c. 8.5 mm; width c. 12.5 mm; h/w c. 0.68; diameters of the first 4 whorls c. 1.5 mm, c. 2.7 mm, c. 4.6 mm, c. 7.0 mm respectively; number of whorls c. 5 5/8, height aperture c. 3.5 mm; width aperture c. 7.0 mm.

Habitat in Sabah and distribution.

Disturbed primary forest on sandstone bedrock, c. 1400 m alt. Sabah: Crocker Range only. Endemic to Sabah.

Cross diagnosis.

Uniquely identified within Geotrochus by the brown, grey and white mottled shell. The convex sides of the shell, combined with the rapidly expanding whorls are also characteristic.

Remarks.

The only shell available is possibly sub-adult. The description of the aperture may need to be amended once more material becomes available.

The pattern of low, vaguely outlined spiral ridges and similar rows of oblique indentations do not occur in any other Geotrochus species.

Etymology.

The name refers to the dirty white apiral band [spilos (Gr.) = stained; keiria (Gr.) = bandage].