A broken tooth lodged in the center of a vertebra, discovered in a museum drawer in Peterborough, England, has given paleontologists a rare window into a lethal encounter between two of the ocean's most fearsome predators—one that unfolded 160 million years ago during the Late Jurassic period.
The fossil captures a moment of predatory violence that had long been suspected but never directly observed: a pliosaur, an imposing marine reptile armed with 5-inch-long, dagger-like teeth, attacking an ichthyosaur—a dolphin-shaped swimmer that itself hunted ammonites and squid for survival. The tip of the pliosaur's tooth shattered as it bit down with such force that it pierced through the ichthyosaur's vertebra at the precise moment of attack, just above the creature's tail. The ichthyosaur's body fell to pieces on the ocean floor, where the pliosaur likely finished its meal.
This discovery matters because it transforms hypothesis into hard evidence. Scientists had long reasoned, through indirect evidence, that pliosaurs preyed upon ichthyosaurs. Now they have proof—a singular fossil that speaks directly across the millennia about survival and predation in ancient seas.
The story began when Caleb Gordon, then a Ph.D. student at Yale, rummaged through a drawer labeled "problematica" in the Peabody Museum's marine reptile collection in September 2024. He picked up a triangular vertebra with something unusual jutting from its center. The specimen label offered only six words of cryptic information, but Gordon's curiosity was immediately fired. "I had initially thought when I saw this fossil that it was an ambush kill," he said. The fossil revealed something remarkable: a tooth tip embedded in the weakest, most fragile part of the vertebra—its very center. That kind of damage required extraordinary force. "That giant tooth in the giant jaw of a giant animal penetrated through the weakest, most fragile part of the vertebra with enough force that the tip of the tooth broke off," Gordon explained.
What followed was detective work spanning the museum's archives. Gordon and Daniel Brinkman, the Peabody's long-serving museum assistant, traced the fossil's complex archival history and tracked down where it had been collected—information critical to identifying the two creatures involved. They brought in Giovanni Serafini from the University of Modena and Reggio Emilia, an expert on ichthyosaur carcasses, who confirmed the fossil came from an ichthyosaur and recognized the bite pattern. "What immediately caught my interest was how the tooth was piercing the vertebra in its exact center," Serafini said.
The three researchers published their findings in the current issue of the Bulletin of the Peabody Museum of Natural History, offering what may be the most direct evidence yet of Late Jurassic predation in European seas. While they cannot entirely rule out the possibility that the pliosaur scavenged an already-dead creature, the evidence leans strongly toward predation—a chaotic, violent moment frozen in stone.
"It's exciting to see a tooth punctured through a vertebra," Gordon reflected. "They are vanishingly rare in the fossil record." For paleontologists who have long studied these leviathans of the past, this one-of-a-kind fossil transforms conjecture into certainty, affirming decades of well-reasoned hypotheses with the weight of direct, undeniable proof.