The shift from the Paleozoic to the Modern (post-Paleozoic) Fauna involved a major influx of benthic molluscs (gastropods and bivalves) into offshore marine environments, resulting in mixed brachiopod–benthic mollusc paleocommunities as early as the late Paleozoic Era; this change might be expected to have affected contemporaneous predators. Gastropods and productidine brachiopods from five upper Pennsylvanian shales in Texas (United States) show greater repair frequencies than do other taxa, suggesting that crushing predators readily consumed gastropods early in the faunal transition but that some brachiopod taxa still composed an important component of predator diets. In contrast, drilling predators continued to prefer brachiopods almost exclusively over benthic molluscs; Paleozoic drillers may have been incapable of taking mobile prey. Contrary to previous hypotheses, brachiopods were probably not “mistaken” prey, at least during the Paleozoic. The addition of gastropods to the diet of crushing predators suggests a major change in ecological processes in response to the new fauna.