A fossil record full of holes: The Phanerozoic history of drilling predation

The evolutionary history of drilling predation, despite a long and rich fossil record (Precambrian Holocene), contains a 120 m.y. gap (Late Triassic Early Cretaceous). Drilled bivalve and brachiopod shells from Jurassic deposits of Hungary, India, and four localities documented in the literature indicate that drillers may have existed continuously throughout the Mesozoic. They may have been descendants of Paleozoic predators, unknown Mesozoic carnivores, or precursors of modern drillers. A literature database suggests three major phases in the Phanerozoic history of drilling predators: (1) the Paleozoic phase (latest Precambrian Carboniferous) dominated by rare to moderately frequent drillings in brachiopods and sessile echinoderms; (2) the Mesozoic phase (Permian Early Cretaceous) with very rare, or even facultative, drillers that had little impact on marine benthic communities, but nevertheless may have been present continuously; and (3) the Cenozoic phase (Late Cretaceous Holocene) dominated by frequent gastropod drillings in mollusks.