Durgella densestriata

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 : 24-25

Taxon classification Animalia Stylommatophora Ariophantidae

' Durgella ' densestriata Vermeulen, Liew & Schilthuizen sp. n. Figure 21

Holotype.

Malaysia, Sabah, West Coast Province, Kinabalu N.P., summit trail, near Layang-layang at 2641 m (Leg. Liew T.S., BOR/MOL 6035).

Examined material from Sabah: West Coast Province, Kinabalu N.P., summit trail (Leg. Liew T.S., RMNH.5003941, BOR/MOL 6036); Kinabalu N.P., Kiau-Spurs route at 2416 m (Leg. T.S. Liew, J. Lapidin & Safrie, BOR/MOL 6034).

Description.

Shell small, membranous, leathery with only a thin calcareous layer on the inside, somewhat translucent, greenish or brownish, low-conical with slightly concave sides; apex narrowly rounded. Surface shiny. Whorls convex, rounded, suture impressed. Protoconch approx. smooth. Teleoconch, radial sculpture: irregularly spaced, somewhat raised growth lines, locally grading into some very fine, inconspicuous, densely placed riblets. Spiral sculpture: above the periphery with very fine, wavy, densely placed, shallow grooves. Peristome not reflected. Umbilicus closed. Dimensions: Height up to 5.5 mm; width up to 6.2 mm; diameter of the first three whorls c. 0.85 mm, c. 1.75 mm, c. 3.7 mm respectively; number of whorls up to c. 3 3/4, height aperture up to 3.8 mm; width aperture up to 3.5 mm.

Habitat in Sabah and distribution.

Primary forest on sandstone or granodiorite bedrock. Alt. 2400-2700 m. Sabah: Mount Kinabalu. Endemic to Sabah.

Cross diagnosis.

We assume this is the shell of an ariophantid semi-slug. Among the genera already reported from Borneo, it fits best in Durgella , Blanford, with regard to the general shell shape and the number of whorls. It differs from Durgella hosei Godwin Austen, 1891, from Sarawak, as well as from continental Asiatic species listed in Blanford and Godwin Austen (1908: 213), Godwin Austen (1916: 555), and Solem (1966: 49) by having a low-conical spire with slightly concave sides, as well as by the fine and dense spiral striation.

Remarks.

Only damaged material was available to us, with some dried remnants of the animal.

Etymology.

The name refers to the shell sculpture [densus (L.) = dense; striatus (L.) = striated].