Plectostoma dormani (Vermeulen, 1994)
Sapulot valley, Sabah, Malaysia.
Sapulot valley, Sabah, Malaysia.
Vermeulen (1994)'s description
"Spire conical with flat to concave sides. Apex not oblique. Whorls 5 3/8 - 7 1/8, convex; last whorl rounded or slightly angular. Constriction with or without a longitudinal palatalis, with transverse palatalis. Tuba gradually narrowed towards the constriction, rounded to slightly angular below. Radial ribs with a swallowly concave to deeply trough-shaped projection half-way, abrading to a scar with a shallow to deep, semi-circular loop (projection of those close to the tuba double-channeled with the upper channel much deeper than the lower, abrading to a distinctly sinuous scar or one with a single deep loop when the shell is observed in front view); those on the spire moderately to wide spaced (2-5 ribs/0.5mm on the penultimate whorl); those on the tuba widely spaced (1-2 ribs/0.5 mm half-way the tuba), below with a slightly curved projection. Spiral striation absent or inconspicuous. umbilicus open, 0.30-0.40 mm across. Aperture tilted up to 30 degrees with regard to the coiling axis, circular to elliptic. peristome simple or double; when simple spreading, often with a somewhat thickened lip inside; when double outer peristome somewhat spreading beyond the inner or not, if so gradually narrowed towards, and absent along the right side of the aperture, often somewhat widened along the upper side; inner peristome usually not or hardly protruding from the outer, spreading. Spire: height 1.9-2.6 mm; width 1.3-1.6 mm; index 1.3-1.7. Total width 2.5-2.9 mm. height aperture 0.6-0.7 mm; width 0.6-0.8 mm."