Although predation has been suggested repeatedly as a force shaping the diversification of animals during the Cambrian period, studies of the evolutionary dynamics of predation are lacking from this time period. Radiodonta, the largest Cambrian nektonic animals, and repaired injuries on trilobites, a diverse and disparate group of prey animals, provide study systems to assess predation dynamics at this time. Radiodont fossils were first discovered over 100 years ago, but are now known worl...