Taxon classification Animalia Stylommatophora Trochomorphidae

Geotrochus paraguensis (E.A. Smith, 1893) Figure 82

Trochonanina paraguensis E.A. Smith, 1893: 349. Type from Philippines, Palawan.

Trochonanina alexis E.A. Smith, 1895: 105, syn. n. Type from Malaysia, Sabah, Banggi Island.

Examined material from Sabah.

Kudat Province. Balambangan Island, Kok Simpul (leg. J.J. Vermeulen & M. Schilthuizen, V 9510, BOR/MOL 2433; leg. T.H. Liew, Sazilin & Ramlan, BOR/MOL 3700); Batu Sireh (leg. J.J. Vermeulen & M. Schilthuizen, V 9547). Banggi Island, South end, Karakit Hill (leg. J.J. Vermeulen, V 1462; leg. J.J. Vermeulen & M. Schilthuizen, V 9475).

Description.

Shell medium-sized, rather thin, opaque, uniformly pale yellowish brown, low-conical with flat to slightly convex sides; apex not protruding or only slightly so. Surface with a silky luster above the periphery, shiny below. Whorls: All whorls moderately convex; suture impressed in the inner whorls, not so in the outer, coinciding with the periphery; last whorl acutely angular, not or hardly compressed at the periphery, moderately rounded below the periphery. Protoconch 1 7/8-2 1/8 whorls, smooth. Teleoconch. Radial sculpture: above the periphery growth lines, raised locally and developing in patches with inconspicuous, somewhat irregularly spaced, fine, low riblets, particularly towards the periphery; below the periphery irregularly spaced growth lines only. Spiral sculpture: last whorl with a sharp but not pinched peripheral ridge; start of fifth whorl with 13-17 well-spaced, very fine and thin spiral threads covering most of the whorl except a narrow strip below the suture, at least some spiral threads close to the periphery usually slightly coarser; no spiral sculpture below the periphery. Umbilicus closed. Peristome thickened and reflexed. Dimensions: Height 6-8.5 mm; width 14-22.8 mm; h/w 0.37-0.42; peripheral keel of the last whorl at 0.39-0.53 of the shell height, measured from the apex; diameters of the first 4 whorls 1.4-1.8 mm, 2.4-2.7 mm, 4.0-4.6 mm, 5.7-6.9 mm respectively; number of whorls 6 3/4-7 5/8, height aperture 3.2-5.2 mm; width aperture 8-11.6 mm.

Habitat in Sabah and distribution.

Dry primary lowland forest, coastal forest on limestone soil. Sabah: Banggi and Balambangan Islands. Distribution: Philippines (Palawan).

Cross diagnosis.

Characterized by the combination of lack of spiral colour bands, the not-pinched periphery, the moderately convex whorls and lower surface of the shell.