Shell description. - The shell is equilaterally triangular in outline, and solid. The shell exterior is bluish white to purplish grey, with reddish-brown rays of varying thickness randomly radiating from the umbones to the ventral edge, although some specimens showed only very little trace of this pattern. The shell sculpture consists of very fine concentric striae. The anterior dorsal margin is slightly convex, and the posterior dorsal margin is almost straight. The anterior end is rounded, connected by a curved ventral edge to the posterior end which is more pointed than the anterior. The umbones are prominent, inflated and rounded, and placed near the mid line of the shell. The lunule and escutcheon are large. The shell interior is light brown to dark reddish-brown, and the areas near the ventral edge are always marked white. The anterior and posterior muscle scars are about the same size. The pallial sinus is shallow, about as deep as it is high, and the pallial line is very thick. The left valve has one anterior and one posterior lateral tooth, and the right valve has two anterior and two posterior lateral teeth.

Distribution. - This species occurs widely in the tropical Indo-Pacific regions, and has been reported from East Africa (Poutiers, 1998), India, Indonesia, Thailand to the Philippines (Vongpanich, 2000), Japan (Kira, 1965; Okutani, 2000), China (Qi, 2000) and Australia (Lamprell & Whitehead, 1992).

Remarks. - Disjointed valves of this species were found scattered on the middle to high shoreline.