Conticosta petilinus is a species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies.

The colour is buff-yellow, with two zones of raw sienna, the one subsutural, the other peripheral.

The ribs are prominently round-backed, arranged at ten to a whorl.

On the upper whorls the spirals are evanescent, and are represented by two or three beads on the ribs.

[2] This marine species is endemic to Australia and occurs off New South Wales