Stepped whorls, deeply incised suture, two spiral ridges, lower one at about a third of whorls diameter, upper one at about two thirds, more pronounced. Upper ridge supports spiral row of spiny tubercles; some specimens with axial ribs; aperture very wide.
Description
Shell : Small to medium sized, conical to turreted, four to five convex, stepped whorls, eroded; colour chestnut brown. Spiral row of spiny tubercles and spiral lines, most prominent at base of shell; last whorl large, inflated; aperture wide, ovate, produced below, comprising up to 1/3 of shell height.
Radula: Ribbon with 120 rows of teeth. Central tooth squarish, anterior rim slightly concave, very large main cusp flanked by two smaller denticles on each side, glabella v-shaped, basely rounded; lateral teeth with main cusp and one accessory denticle on each side; inner and outer marginals with large, broad, spatula-shaped outer cusp and much smaller, pointed inner denticle; inner marginals broader than outer ones.

Similar to spiny morphs of B. costula, but shell not as highly turreted, whorls much more stepped; radula differs in shape of glabella.

India: Meghalaya, Assam, Manipur: tributaries of Brahmaputra (possibly also neighbouring regions of Myanmar and Bangladesh). Seemingly restricted to mountainous regions.