Plectostoma decrespignyi (Adam, 1865)
Limestone hill in Teck Guan Estate, Lahad Datu, Sabah, Malaysia.
Limestone hill in Teck Guan Estate, Lahad Datu, Sabah, Malaysia.
Adam (1865)'s description
"P. testa elevato.conica, tenuissima, pallido-fulva, laminis numerosis longitudinalibus tenuibus erectis munita, sutura valde impressa, apice subacuto; anfractibus 6, convexis, ultimo tubam protractam, postice paulum constractam, sursum flectam, inde revertam efformante; umbilico aperto; apertura circulari, subverticali, paululum reclinante; peristomate libero, valde expanso, reflexiusculo. Diam. major 2, minor 1 1/4, axis 2 mill."
Vermeulen (1994)'s description
"Spire conical with flat to slightly concave sides. Apex slightly oblique or not. Whorls 5 3/8 - 5 7/8, convex; last whorl rounded. Constriction with an inconspicuous and often somewhat irregular shaped parietalis, a similar longitudinal palatalis, a transverse palatalis, a knob-shaped columellaris abruptly ending towards the basal side of the constriction. Tuba gradually narrowed towards the constriction, rounded below. Radial ribs moderately spaced (4-6 ribs/0.5 mm on the penultimate whorl, 3-4 ribs/0.5 mm half-way on the tuba0. not sinuous (rarely slightly so). Spiral striation fine. Umbilicus open, 0.25-0.30 mm across. Aperture tilted up to 30 degree with regard to the coiling axis, circular. Peristome (somewhat) distant from the spire, double; outer peristome hardly spreading beyond the inner, but gradually narrowed towards, and absent narrow along the right side of the aperture, slightly widened along the upper side; inner peristome slightly protruding from the outer, spreading. Spire: height 1.7-1.9 mm; width 1.2-1.3 mm; index 1.4-1.6. Total width 2.2-2.3 mm. Height and width aperture 0.5-0.6 mm."