Petroxestes is a shallow, elongate boring (a type of trace fossil) originally found excavated in carbonate skeletons and hardgrounds of the Upper Ordovician of North America.

[2][3] These Ordovician borings were likely made by the mytilacean bivalve Corallidomus as it ground a shallow groove in the substrate to maintain its feeding position.

[4] They are thus the earliest known bivalve borings.

[5] Petroxestes was later described from the Lower Silurian of Anticosti Island (Canada).

[6] and the Miocene of the Caribbean.