Evidence for chemical boring in Petricola lapicida (Gmelin, 1791) (Bivalvia: Petricolidae)

Specimens of the dead coral-boring bivalve Petri-cola lapicida have been obtained from Thailand and Jamaica. Although formerly concluded to be a mechanical borer, examination of the burrow and the shell strongly suggests chemical boring. Two glands located in the inner mantle folds around the antero-ventr'al pedal gape are thought to be involved in this, although one may secrete the calcareous material cemented to the posterior shell margin

Less specialised petricolids are mechanical borers of stiff muds, shales and calcareous rocks. A few are nestlers, e.g., Claudiconcha. As has been recently suggested for other families of borers, the Petricolidae constitute another example of the evolution of a specialised chemical borer from a less specialised mechanically-boring ancestor,