2023-07-18 18:07:43
Mammals existed long before dinosaurs disappeared 66 million years ago. However, they were completely overshadowed by Tyrannosaurus rex & Co. – although both groups of vertebrates entered the biosphere stage at the same time around 230 million years ago. The dinosaurian mammals are usually described as resembling mice or martens, as shy, nocturnal small animals that, if they were predatory at all, fed on insects. If they had anything to do with dinosaurs, it was as their prey.
Ulf von Rauchhaupt
Editor in the “Science” section of the Frankfurter Allgemeine Sunday newspaper.
However, as early as 2005, Chinese researchers had Nature published the find of fossil skeletal remains of a mammal from the Lower Cretaceous of China, which she Let’s call it gigantic baptized, since he was after all larger than a domestic cat. But that’s not all: Bones of dinosaur chicks were found in the petrified contents of the animal’s stomach. They were juveniles of the genus Psittacosaurus and thus a herbivore that grew to at least the size of a shepherd dog and was a distant relative of the Late Cretaceous Triceratops. Apparently, the largest mammal of the Cretaceous period, which has been handed down in reasonably meaningful fossils, had used a dinosaur nest here.
But now a team of Chinese and Canadian paleontologists led by Gang Han from Hainan Tropical Ocean University in the journal Scientific Reports described a most amazing fossil. It was found back in May 2012 in the same Cretaceous deposits as the one mentioned Let’s call it gigantic: the Yixian Formation near Lujiatun in northeast China’s Liaoning Province. The fossil preserves two interlocked vertebrate skeletons: the larger one is from an adult Psittacosaurus, the other from a slightly smaller congener of the R. giganticuswhose kind Let’s call him strong again has been known for a long time.
Fossil of a Psittacosaurus lujiatunensis dinosaur in agony with a Repenomamus robustus. Enlarged out: R. robustus left front paw grips P. lujiatunensis lower jaw (left), R. robustus skull including two ribs of its victim (middle), mammal’s hind paw between hind leg bones of Psittacosaurus (right). The measuring scale is 10 centimeters long. : Image: Gang Han
The fossil preservation is so good that even a layman can quickly see what happened here: the mammal sits on the three times heavier dinosaur and bites its torso. He has two ribs between his teeth. At the same time, his left front paw has a grip on the beaked lower jaw of the Psittacosaurus, while the left rear paw claws at the dinosaur’s lower leg. Apparently – so the authors of the publication conclude after a thorough analysis – the comparatively small mammal has misused a significantly larger, fully grown dinosaur.
“When I first saw the image of this fossil, it took my breath away,” says University of Edinburgh paleontologist Steve Brusatte, a specialist in dinosaurs and early mammals. “I had never seen anything like this before. It is unlikely that even a piece of bone or a tooth could be preserved for 125 million years, let alone a complete dinosaur skeleton – but two animals together in deadly combat is a miracle.”
In Chinese Pompeii
In fact, it is thanks to a volcanic eruption that this scene from prehistoric times could come to us in such a snapshot-like manner: Just at the moment when predator and prey were in a deadly clinch with one another, they must have been caught by a so-called lahar, a mudslide of volcanic ash and water, which is released during eruptions in connection with meltwater or rainwater and floods the landscape with a material that after a short time hardens like concrete. In this case, it was about 125.7 million years ago, according to radiometric dating of the solidified lahar material.
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