Ditropopsis davisoni 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 : 11-12

Taxon classification Animalia Architaenioglossa Cyclophoridae

Ditropopsis davisoni Vermeulen, Liew & Schilthuizen sp. n. Figure 9

Holotype. Malaysia, Sabah, Upper Padas valley , Matang River South of Long Pasia (leg. J.J. Vermeulen, RMNH.5003917 ).

Description.

Shell very small, rather thick, somewhat translucent, whitish. Surface shiny. Teleoconch whorl entirely detached, more or less in one plane; apex protruding from the plane, distinctly oblique. Sculpture. Radial sculpture: fine growth lines, locally grading into fine, densely placed riblets. Spiral sculpture on the last whorl: 8 cords (position as on the first part of the teleoconch, close to the protoconch): 1 supraperipheral, 1 peripheral, 1 basal, these three distinct, and 5 umbilical, the outer 2 distinct, the inner 3 more inconspicuous; next to these a fine spiral striation on the lower surface. Sculpture continuing up to the peristome. Aperture. Peristome simple, not expanded, angular where the spiral cords meet the peristome. Dimensions. Height c. 0.7 mm; width c. 1.5 mm (both measured along the axis of the teleoconch); height and width aperture c. 0.5 mm.

Habitat in Sabah and distribution.

Found in montane forest, in a sandstone rock crevice near a small stream in thick leaf litter, at 1100 m alt. Sabah: Upper Padas River. Endemic to Sabah.

Cross diagnosis.

Uniquely identified among the Sabah species by the tubular, detached teleochonch.

Species from elsewhere with a detached teleoconch are Ditropopsis adesmospira Moellendorff, 1895, Ditropopsis mira Moellendorff, 1891, (both from the Philippines) Ditropopsis spiralis Boettger, 1891 (from Maluku) and Ditropopsis biroi Soós, 1911 (from Papua New Guinea). All have a protoconch which protrudes from the teleoconch, and a conical spire.

Etymology.

Named in honour of Dr. Geoffrey Davison, tireless advocate of nature conservation in Southeast Asia.