Tropidoturris fossata is a species of sea snail, a marine gastropod mollusk in the family Borsoniidae.

Its color is pale fulvous, obscurely spotted with brown, here and there tinged with light purple, and coloured anteriorly with a purplish band.

The rest is deeply concave at the top, the concavity being bordered by a sharp erect keel, below which the whorls are slightly convex, with short very oblique plicae, and about 5 spiral lirae which are sharply angular at the top and slopingly compressed on the under side.

The body whorl ais bout equal in length to the spire, slightly convex above, and tapering to the base.

The sharp erect keel at the top of the whorls, the broad channel between this and the suture, and the numerous curiously sloping spiral lirae throughout, are its chief characteristics.