Giant Xiphactinus likely killed a Polycotylus plesiosaur in a prehistoric predator clash
CT scans of a Polycotylus plesiosaur fossil reveal a giant Xiphactinus tooth lodged in its neck, providing direct evidence that top predators in Cretaceous seas fought or attacked each other; the bite likely contributed to the plesiosaur’s death and highlights a violent prehistoric ecosystem where apex predators occasionally clashed.