GASTROPOD DRILLING PREDATION IN THE UPPER JURASSIC OF KUTCH, INDIA

While records of drilling predation are abundant across the Phanerozoic, it has been argued to suffer a decline in the Mesozoic due to failed radiation of unknown facultative drillers. In this study, we present a new dataset of gastropod drilling predation on the Kimmeridgian and Tithonian (Upper Jurassic) bivalves of Kutch, India. Our study suggests that drilling was a common mode of predation in the Upper Jurassic of Kutch with variable intensities, ranging from 2% in the Kimmeridgian Seebachia to 26% in the Tithonian Pinna. Higher drilling intensity in the diverse Tithonian molluscan community, compared to the low-diversity Kimmeridgian, can be explained by change in relative sea-level and associated depositional environment. Morphology of these drillholes and recent recovery of body fossils from the same stratigraphic units enable us to unequivocally designate naticid gastropods as the responsible drillers. A literature survey reveals that lack of predatory gastropod body fossils and proper sampling perspective often lead to the hypothesis of reduced drilling predation intensity in the Mesozoic.