An article published in the journal “Gondwana Research” reports the discovery of an ichthyosaur fossil in present-day Australia that preserved the contents of its stomach, which includes the remains of a pterosaur. The ichthyosaur itself shows remarkable signs of having been bitten by a pliosaur, which literally broke its bones. A team of researchers led by Dr. Matt White of the University of New England studied these fossils and reconstructed this snapshot of the ecosystem in which these animals lived during the Cretaceous Period. The result reveals a portion of the food chain that existed in that area approximately 100 million years ago.

In 2019, fossil bones that were initially unidentified were discovered in the Toolebuc Formation in Queensland, Australia. The discoverers nicknamed them “Bag of Bones” (B.O.B.) and catalogued them. Only three years later, more bones were excavated of what was identified as an ichthyosaur, specifically a Platypterygius australis.

This is a species of ichthyosaur that was assigned to a genus that includes a rather heterogeneous group of species, which were widespread throughout most of the world during the Cretaceous. The species Platypterygius australis was comparable in size to a modern orca.

Some strange rock nodules were identified by the researchers in the fossils and led to further investigations. The option of breaking pieces of rock was discarded, and the fossils were sent to the Australian Nuclear Science and Technology Organisation (ANSTO), where they were subjected to a type of CT scan that enabled them to produce a 3D reconstruction of the Platypterygius australis and study its strange features. nodules.

The results of the examination identified the fossil remains of the last meal the Platypterygius australis had. These remains include fragments of bony fish and cephalopods, which the researchers expected from an ichthyosaur’s meal. Far more surprising was the discovery of a fragment of a pterosaur’s jaw. The bone wasn’t enough to identify the species, but its characteristics led the researchers to attribute it to a pterosaur of the Ornithocheiroidae group.

It’s likely that the ichthyosaur was flying over that ancient ocean hunting fish or other small aquatic prey when it became prey itself, captured and eaten by the Platypterygius australis. This is the first time evidence has been found that ichthyosaurs ate pterosaurs.

This discovery was already exceptional, but the investigation provided further results that make it unique. This is because the Platypterygius australis’ bones show bite marks from a truly powerful animal, which crushed the ichthyosaur’s bones. The researchers believe the culprit was a Kronosaurus queenslandicus, a pliosaur that could reach 10 meters in length and was a top predator in the ecosystem where it lived.

In essence, the Platypterygius australis hadn’t yet digested its meal when a Kronosaurus queenslandicus killed it. This is one of the best examples of fossils showing a predatory interaction between three different species within an ecosystem. Modern technology allows for examinations that were impossible just a few decades ago. In this case, the result allowed to reconstruct part of the food chain that existed in that area approximately 100 million years ago.

The bottom image (Gondwana Research (2026). DOI: 10.1016/j.gr.2026.05.014) shows a graphical representation of the possible food chain that includes the interaction examined in this study.