100M-Year-Old Fossil Captures Three-Tier Predator Chain in Ancient Sea

In the rocks near Richmond, Queensland, scientists have found something that reads like a moment frozen in time: a marine reptile caught mid-meal, itself the victim of a larger predator. The fossil tells a three-act story of hunger and death that unfolded roughly 100 million years ago, when central Queensland lay beneath the Eromanga Sea.

At the heart of the discovery is an ichthyosaur—a dolphin-shaped marine reptile measuring between six and seven metres long—preserved in stone with the remains of a pterosaur lodged in what was once its stomach. But the ichthyosaur's skeleton bears the unmistakable signature of violence: massive crushing bite marks, shattered bones, and sections torn away. These wounds match the attack pattern of Kronosaurus queenslandicus, a giant pliosaur that dominated the inland Queensland sea as an apex predator. What scientists have uncovered is a rare window into the food chain of an ancient ocean, a moment when predator became prey.

The story of how this fossil came to light began in August 2019, when two couples—Mike and Cathy Freeman, along with Gary and Barb Flewelling—were fossicking near Richmond and uncovered large bones. They collected the fragments, bagged them, and gave them a working name: BOB, for Bag Of Bones. The material sat until 2022, when Kevin Petersen, a curator, returned to the site and excavated the rest of the ichthyosaur's skeleton, which stretched nearly eight metres. What followed was painstaking work: more than 600 hours of volunteer and staff time went into preparing the fossil for study.

The real breakthrough came when researchers noticed unusual rock nodules positioned behind the skull. Rather than risk destroying the fossil by breaking the rock open, they sent the specimen to the Australian Nuclear Science and Technology Organisation, where scientists used advanced neutron tomography to peer inside without causing damage. What they found hidden in the stone were fish, squid-like cephalopods, and fragments of a flying reptile's jaw—the remains of the pterosaur that had been the ichthyosaur's last meal.

Dr. Dean Lomax, an internationally recognized palaeontologist who visited Australia to examine the find, called it one of the clearest examples ever discovered of a three-tier predator interaction. "This extraordinary fossil records a trophic interaction between a pterosaur eaten by an ichthyosaur that was then partly consumed by a giant pliosaur," he said. "It gives us direct evidence of behaviour in the Eromanga Sea." Dr. Matt White, the lead author of the study published in the journal Gondwana Research, expressed similar wonder. He described being amazed by the ichthyosaur's size and shocked to see it covered in bite marks with pterosaur remains visible behind the skull.

Beyond the scientific significance, the discovery illustrates something broader about how knowledge moves through the world. Karen Hanna Miller, executive officer of Dinosaur Experiences Australia, points out that Queensland's prehistoric finds have become a draw for visitors, and that tourism and scientific research feed each other. "Scientific discovery provides the stories that inspire travel while tourism helps those stories reach the world," she says. The fossil itself—a moment of predation preserved in stone—has become a bridge between the laboratory and the public imagination, a reminder that the most compelling science is often the simplest: one creature eating another, and being eaten in turn.