Scientists discover an incredible, perfectly preserved fossil of a small mammal that chewed on a dinosaur

A fossil of two intertwined skeletons discovered in China shows for the first time that a mammal could have attacked a dinosaur much larger than itself 125 million years ago

The badger-sized mammal was digging its fangs into the ribs of a dinosaur three times its size when the two were frozen in the ash of a volcanic eruption 125 million years ago, a remarkably well-preserved fossil.

A battle scene in a very well-preserved fossil discovered in China suggests that small mammals could have attacked the dinosaurs that dominated the fauna of the Cretaceous period, researchers explain in the journal Scientific Reports published on Tuesday, July 18, 2023.

“I couldn’t believe my eyes”

According to Jordan Mallon, a paleontologist at the Canadian Museum of Nature who co-authored the study led by Chinese scientists, this is the first time a fossil has been discovered showing a fight between a mammal and a dinosaur. With the discovery of a fossil, “I couldn’t believe my eyes”, he told AFP.

Until now, mammals were thought to be too small to have attacked the dinosaurs during the tens of millions of years they lived side by side.

However, the fossil shows Repenomamus robustus towering over Psittacosaurus lujiatunensis, a four-legged herbivore with a parrot-like beak.

We can clearly see the mammal, one of the largest of its time but only a third of the dinosaur’s weight, snapping its prey’s sharp fangs into the ribs while clutching its hind leg.

A reconstruction of the scene that took place 125 million years ago before it was immortalized in stone.  (MICHAEL W. SKREPNICK / CANADIAN MUSEUM OF NATURE / AFP)

“Fire Mammals”

According to Jordan Mallon, the way the two skeletons are intertwined shows that the mammal did not eat the dinosaur’s carcass. The dinosaur collapsed, trapping the mammal’s hind leg in the bend of its knees.” suggesting a mammal attack, the paleontologist notes.

The dinosaur skeleton bears no other bite marks typical of those left by an animal that ate a carcass.

Although it is rare for mammals to attack animals much larger than themselves, there is still an example of a wolverine being observed attacking a caribou much larger than itself.

The fossil did not allow us to determine whether Repenomamus robustus hunted alone or in packs.

Two skeletons, nearly complete, were discovered in 2012 in Liaoning, a province in northeastern China.

Dubbed the “Pompeii of China,” the site is home to many remains of dinosaurs and other animals preserved in volcanic debris similar to that of an ancient Roman city.

The first fossil discovered in 2005 suggested that mammals could feed on dinosaurs. It turns out that the little Psittacosaurus ended up in Repenomam’s stomach.

But this new fossil is the first evidence that it does “in the Cretaceous (…) there were at least a few fiery mammals capable of giving birth to an he dinosaur”, according to Jordan Mallon.

The discovery will be exhibited in a museum attached to a primary school in the Chinese city of Weihai.

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