Kaliella microsoma 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 : 78-79

Taxon classification Animalia Stylommatophora Euconulidae

Kaliella microsoma Vermeulen, Liew & Schilthuizen sp. n. Figure 69

Holotype. Malaysia, Sabah, West Coast Province , Crocker Range N.P. , km 54 marker on the road Kota Kinabalu-Tambunan , Gunung Mas ( RMNH.5003926 ).

Examined material from Sabah.

Interior Province. Upper Padas valley, Matang River South of Long Pasia (leg. J.J. Vermeulen, V 9817). West Coast Province. Crocker Range N.P., km 54 marker on the road Kota Kinabalu-Tambunan, Gunung Mas (leg. J.J. Vermeulen & M. Schilthuizen, V 9767).

Description.

Shell very small, very thin, somewhat translucent, greenish-brown, conical with slightly convex sides; apex rounded. Surface with a silky luster. Top whorls convex, outer whorls only a little less convex, last whorl angular at the periphery, somewhat obtusely so near the aperture in adult specimens, moderately convex below the periphery. Protoconch whorls convex, with very fine, densely placed radial riblets; spiral sculpture subordinate and sometimes inconspicous, very densely placed grooves, just visible at 40 times magnification. Teleoconch: Last whorl with a peripheral spiral thread coinciding with the suture of the penultimate whorl, above the periphery fine, moderately spaced, narrow spiral grooves that cut into the crests of the radial riblets and that are slightly to distinctly subordinate to these; below the periphery with similar, but slightly more distinct and slightly more spaced grooves. All spiral sculpture varies from rather distinct to inconspicuous and only locally present. Radial sculpture teleoconch: above the periphery rather inconspicuous, irregularly spaced, somewhat raised growth lines, next to these fine, very densely and regularly placed riblets on the inner whorls, less densely placed riblets locally present on the outer whorls; radial sculpture less conspicuous below the periphery. Umbilicus closed. Dimensions: Height up to 1.6 mm; width up to 1.8 mm; diameters of the first three whorls 0.45-0.55 mm, 1.0-1.2 mm, 1.65-1.90 mm respectively; number of whorls up to c. 3 3/8; height aperture up to 0.85 mm; width aperture up to 1.0 mm.

Habitat in Sabah and distribution.

Primary forest on sandstone soil. Alt. 1100-1700 m. Sabah: upper Padas River valley; Crocker Range. Endemic to Sabah.

Cross diagnosis.

General shape as in Kaliella gregaria , but much smaller (check the diameters of the first three whorls), slightly higher conical and with more convex whorls. The spiral sculpture is generally coarser then in Kaliella gregaria , but may be very inconspicuous in specimens from the Crocker Range (including the illustrated shell which, on the lower surface, has spiral sculpture only near the aperture).

Etymology.

The name refers to the small size [mikros (Gr.) = small; soma (Gr.) = body].