Amalda petterdi is a species of sea snail, a marine gastropod mollusk in the family Ancillariidae.

[1] (Original description as Ancillaria obtusa) The shell is ovate, thick, and glossy, ranging in color from white to pale fulvous.

It has approximately five whorls, with a short, rounded spire lined and covered by a thick callous deposit.

The body whorl is bordered by broad, milky zones at both the upper and lower edges and displays linear markings at the base.

The columella is coated with a thick layer of enamel that extends onto the body whorl and appears slightly wrinkled and twisted near the siphonal canal.