Taxon classification Animalia Architaenioglossa Cyclophoridae

Ditropopsis trachychilus Vermeulen, Liew & Schilthuizen sp. n. Figure 10

Holotype. Malaysia, Sabah, West Coast Province, Crocker Range N.P., near the km 54 marker on the road Kota Kinabalu-Tambunan, Gunung Mas (leg. J.J. Vermeulen & M. Schilthuizen, RMNH.5003918).

Examined material from Sabah.

West Coast Province, Kinabalu N.P., summit trail, between 2308-2775 m (leg. T.S. Liew, BOR/MOL 4121, BOR/MOL 4113); Bowen route at 3376 m (leg. T.S. Liew & Jasilin, BOR/MOL 4111); Mesilau trail between 2092-2356 m (leg. T.S. Liew, BOR/MOL 4119, BOR/MOL 4114); Kotal’s route between 2924-3048 m (leg. T.S. Liew, J. Lapidin, Safrie & Jasilin, BOR/MOL 4117, BOR/MOL 4115; leg. T.S. Liew & Jasilin, BOR/MOL 4118); Sayap-Nunuhon trail between 2640-2944 m (leg. T.S. Liew, Dominik, J. Lapidin & Jasilin, BOR/MOL 4116, BOR/MOL 4112, BOR/MOL 4120, BOR/MOL 4123, BOR/MOL 4124).

Description.

Shell very small, rather thick, hardly translucent, pale greenish. Surface shiny. Spire rather high-conical. Radial sculpture: fine growth lines, locally grading into fine, densely placed riblets. Sculpture. Spiral sculpture on the last whorl: 4 cords: 1 supraperipheral and 1 peripheral, about equally wide, 1 basal; these all rather distinct; 1 umbilical, inconspicuous and located deep inside the umbilicus; next to these a fine spiral striation on the lower surface. This sculpture continuing up to about 0.8 mm from the peristome, to be replaced by densely and irregularly placed radial riblets with a periostracal crest. Aperture. Peristome simple, not expanded, parietal side slightly detached from the penultimate whorl, basal side rounded, hardly drawn out. Dimensions. Height c. 2.3 mm; width c. 2 mm; h/w c. 1.15; umbilicus measured over the basal spiral cord c. 25 % of the shell width; number of whorls c. 4 1/8; height aperture c. 0.8 mm; width aperture c. 0.8 mm.

Habitat in Sabah and distribution.

Primary montane oak forest on sandstone bedrock, in leaf litter, sub-alpine forest on ultrabasic and granodioritic bedrock, 1300-1400 m (Crocker Range), 2000-3400 m (Mount Kinabalu) alt. Sabah: Mount Kinabalu, Crocker Range. Endemic to Sabah.

Cross diagnosis.

Similar to Ditropopsis koperbergi, but shell higher conical. The distinctive sculpture near the aperture develops only when fully adult, as in other species of the genus.

Ditropopsis gradata Quadras & Moellendorff, 1896 and Ditropopsis pusilla Quadras & Moellendorff, 1895, from the Philippines, have a similarly high spire and spiral cord distribution. Both species have a more rounded profile to the whorls.

Etymology.

The name refers to the peristome [trachus (Gr.) rough; cheilos (Gr.) = lip].