Updated

Updated · Popular Science · Jul 29

40-Foot Kronosaurus Caps 3-Tier Fossil Food Chain in 100-Million-Year-Old Australian Sea

Updated

Updated · Popular Science · Jul 29

40-Foot Kronosaurus Caps 3-Tier Fossil Food Chain in 100-Million-Year-Old Australian Sea

Q: What other ancient secrets did advanced scanning reveal hidden within the stomach of this doomed Cretaceous sea monster?

Advanced scanning revealed that the ichthyosaur’s stomach contents held more than just the pterosaur. Researchers found remains of fish, squid-like cephalopods, and fragments of a pterosaur lower jaw preserved inside rock concretions behind the skull. Those details came from non-destructive imaging at ANSTO, using synchrotron CT and neutron-based scanning to look inside the dense nodules without breaking them apart. The location of the concretions, directly behind the skull, helped scientists identify them as fossilised gut contents. The pterosaur material was especially important because it provided what researchers described as the first definitive evidence that an ichthyosaur had eaten a pterosaur. The additional fish and cephalopod remains also showed that the animal had a varied diet, offering a fuller picture of the food web in the ancient Eromanga Sea.

Q: How did a marine reptile manage to capture a flying pterosaur just moments before being crushed by an apex predator?

No one knows exactly how it happened, but researchers say the most plausible answer is that the ichthyosaur caught the pterosaur at or near the water’s surface, where flying reptiles would have been vulnerable while skimming, resting, feeding, or taking off. The fossil does not preserve the moment of capture, only the aftermath: pterosaur jaw fragments in the ichthyosaur’s gut, alongside fish and cephalopod remains, show the marine reptile had swallowed it shortly before death. Because those remains were still in the stomach region, scientists infer the meal was recent. Palaeontologists have suggested two broad scenarios. The ichthyosaur may have snatched a low-flying pterosaur from the surface, much as modern marine predators seize seabirds. Or the pterosaur may already have been floating, injured, or feeding on the water when it was taken. Dr Matt White has said the exact sequence cannot be known, and even whether the ichthyosaur was breaching or the pterosaur was on the surface remains uncertain. What is clearer is what came next. The ichthyosaur’s trunk was crushed and scored by more than 30 large bite marks, damage researchers say matches an attack by Kronosaurus queenslandicus, the only known predator in the Eromanga Sea large enough to inflict that kind of trauma. So the fossil strongly supports a rapid chain of events: pterosaur eaten by ichthyosaur, then ichthyosaur attacked and partly consumed by a giant pliosaur.

3 articles · Updated · Popular Science · Jul 29

Queensland fossils show a 23-foot ichthyosaur had swallowed a pterosaur before it was attacked and partly eaten by a 40-foot Kronosaurus, giving paleontologists their first fossilized three-tier food chain.
600 hours of preparation and synchrotron CT scans of nearby rock nodules exposed the ichthyosaur’s last meals—cephalopods, fish and a flying reptile jaw—without damaging the specimen.
Bite marks, pulverized bone and missing chunks on the ichthyosaur matched Kronosaurus, a short-necked pliosaur estimated at 11 to 13 tons with a bite force of 3,370 to 6,070 pounds.
The remains were first spotted in 2019 near Richmond by hobbyist fossil hunters whose stored "Bag of Bones" was later examined by Kronosaurus Korner staff and researchers.
Published in Gondwana Research, the find offers one of the clearest snapshots yet of predator-prey behavior in Australia’s Cretaceous Eromanga Sea.

Sources

Popular Science11d ago

Fossilized Three-Tier Food Chain: Kronosaurus Ate Ichthyosaur That Ate Pterosaur in Australian Outback

New York Post 11d ago

"Bag Of Bones" Fossil Reveals Cretaceous Three-Tier Predator Interaction

IFLScience11d ago

New Study Reveals Lower Cretaceous Ichthyosaur Ate Pterosaur, Bitten by Pliosaur in Australia

7 Sources

What other ancient secrets did advanced scanning reveal hidden within the stomach of this doomed Cretaceous sea monster?

Could this prehistoric 'crime scene' actually be a case of opportunistic scavenging rather than a brutal, multi-level ocean hunt?

How did a marine reptile manage to capture a flying pterosaur just moments before being crushed by an apex predator?

"Frozen in Time: The 100-Million-Year-Old Kronosaurus–Ichthyosaur–Pterosaur Food Web Uncovered in Outback Queensland"

Overview

In 2019, amateur fossil hunters discovered a mysterious set of bones, nicknamed 'B.O.B.', at a public site near Richmond, Queensland. Years later, museum experts and volunteers excavated the site, revealing a giant ichthyosaur skeleton with severe bite marks. Scientists identified the predator as Kronosaurus queenslandicus. Behind the skull, rock nodules were found and sent to ANSTO, where advanced neutron scans uncovered the ichthyosaur’s last meal: fish, cephalopods, and a pterosaur jaw. This evidence, published in 2026, documented a unique three-tier prehistoric food chain, earning global scientific acclaim for its insight into ancient marine life.

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