The victim of its attack was Psittacosaurus lujiatunensis, a bipedal, plant-eating beaked dinosaur – and a distant relative to the later triceratops – which was about the size of a cocker spaniel. The fossilised mammal, discovered in the Lujiatun member of the Lower Cretaceous Yixian formation in China in May 2012, was identified by the team as Repenomamus robustus – an ancient creature about the size of a domestic cat. Even the smaller mammals could pose a threat, foreshadowing their rise to dominance 66m years ago.” 'I've never seen a fossil like this before,' Dr Mallon said.Researchers said the discovery challenged a long-held view of early mammals as “fodder” for dinosaurs.ĭr Jordan Mallon, a co-author of the study, based at the Canadian Museum of Nature, said: “This new fossil teaches us that in the Mesozoic ‘age of dinosaurs’, dinosaurs were not always king. The mammal is perched on the dinosaur, its paws gripping the reptile's jaw and a hind limb while its teeth plunge into the dinosaur's rib cage. The fossil, described in the journal Scientific Reports on Tuesday, shows two creatures from around 125 million years ago, during the Cretaceous period.Įven though the mammal is much smaller, researchers believe it was in the process of attacking the dinosaur when they were both caught in the volcanic flow, said study author Jordan Mallon, a palaeobiologist at the Canadian Museum of Nature.

'It does seem like this is a prehistoric hunt, captured in stone, like a freeze frame,' said University of Edinburgh palaeontologist Steve Brusatte, who was not involved with the study.

The find comes from a site known as 'China's Pompeii', where mud and debris from long-ago volcanoes buried creatures in their tracks. The fossil shows a badger-like creature chomping down on a small, beaked dinosaur, their skeletons intertwined.

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