Shell: Size up to 26 mm long, mean w/1 ratio 0.71, mean h/1 ratio 0.36. Symmetrical, boat-shaped as the apex curves towards the ventral side and the apex is ground flat on the ventral surface. Apex is small, pointed and outside the posterior shell margin. Shell widest in front of the septum, which is deeply concave and curved towards the apex. Ground colour yellow brown with faint darker markings forming long, narrow stripes changing to small triangles on the apex. When the animal is in the shell, the foot is dark gray. The shell inside is gray and the septum white turning bright pink or yellow-orange near the small apex. Male and female individuals are approximately the same size and populations have the same number of each sex. Operculum: robust, rib and anterior white turning yellow and black at the posterior. Has a clear, dark orange horn margin.

S. luzonica can be confused with female S. suffreni as its shape and yellow-orange septum are similar. I believe that FRANC (1957) confused the two and that S. luzonica from New Caledonia is in fact S. suffreni. Others e.g. STARMUHLNER (1970) and POLLABAUER (1986) did not find S. luzonica in New Caledonia.

Philippines, Indonesia and West New Guinea. On stones and boulders in fast flowing streams from near the sea to a few kilometers inland.