Petroxestes pera Wilson et Palmer, 1988

Diagnosis. — Shallow to deep, elongate borings in lithic sub­strates; rounded ends and parallel, slightly convex, or slightly concave sides in plan view; rounded bottoms in longitudinal and transverse section; sides parallel or slightly divergent down­ wards in deeper specimens; length up to 30 mm; several times as long as wide.

Ecological remark. Petroxestes pera is found both on the upper surfaces and undersides of cobbles and hardgrounds, but usually only on the undersides of biogenic substrates.