Boreholes in Mississippian spiriferide brachiopods and their implications for Paleozoic gastropod drilling

Bored specimens of the spiriferide brachiopod genera Brachythyris and Spirifer from several localities of the Mississippian Fort Payne Formation (Kentucky, USA) represent 7.0% of the total sampled population. The boreholes are typically single, complete, circular in plan view, and with their long axes perpendicular to the valve. These traits and stereotypy with respect to the pedicle valve and the fold and sulcus are consistent with a predatory/parasitic origin of the holes. The presence of platyceratid gastropods in the Fort Payne localities with bored brachiopods, the previously documented drilling abilities of these gastropods, and the occurrence of a platyceratid snail attached to specimen of a bored Devonian brachiopod, Atrypa, argue for platyceratids as the most probable culprits.