“The new species is very similar to the preceding one. It possesses, however, fewer whorls and is not quite so slender as O. (P.) turriforme.” (Benthem-Jutting, 1952)
Benthem-Jutting (1952) original descriptions on Opisthostoma (Plectostoma) sciaphilum – “Shell high-turreted, yellowish, fawn or pinkish-brown. First 1 ½ whorl smooth, subsequent ones ornamented with elegant, oblique white ribs, distantly placed and standing out wing-like away from the shell. This is especially the case on the periphery of each whorl, rendering their profile falsely angular. Between the ribs there is a delicate spiral sculpture. Not transparent and only little shining. Whorls 7-7 ½, convex, regularly increasing in size. Top whorls not markedly oblique on the rest of the shell. Last whorl about midway somewhat constricted transversely, then widening towards the aperture and irregularly curved, although not so bizarre as in O. (P.) salpidomon and previous species. Suture deep. Umbilicus closed. Aperture round, vertical or a little obliquely facing downward. Adnate to the previous whorl. Peristome continuous, circular, with a wing-like ribs behind the peristome and parallel to it. Operculum unknown.”
Opisthostoma (Plectostoma) sciaphilum – “Dimensions: Height 3.0-3.6, Breadth 1.5-1.6, Diam. apert. 0.9-1.1 mm.” (Benthem-Jutting, 1952)
Type locality – “Malaya: Bukit Panching, near Kuantan, Pahang” (Benthem-Jutting, 1952)