July 23, 2023: A remarkable fossil documents the attack on a dinosaur by a predatory animal. Continue reading to know more!
A hungry Repenomamus, an ancient mammal the size of an opossum, attacked an unwary Psittacosaurus, a herbivorous dinosaur more than three times its size, during the Cretaceous period 125 million years ago. One of the mammals' hind legs was pinned beneath the dinosaur as its front paw grabbed hold of the dinosaur's beak as they struggled. Additionally, the Repenomamus was biting into the reptile's ribs.
Both the mammal and the dinosaur were ultimately doomed in this battle. A surge of volcanic debris from a nearby eruption buried the intertwined animals mid-scuffle, preserving both predator and prey in stunning detail. The amazing fossil, which was revealed in Scientific Reports on Tuesday, gives scientists their first look at a Mesozoic mammal aggressively pursuing a much larger dinosaur.
The Mesozoic (252–66 million years ago), also known as the time of the dinosaurs, is defined as "middle life." The Triassic, Jurassic, and Cretaceous Periods are all included in this era.
The positions are reversed, according to palaeontologist Stephen Brusatte of the University of Edinburgh, who was not involved in the new study. "You would surely assume that it was the dinosaur eating the mammal, but the roles are reversed," he adds. It's similar to seeing a coyote grab a roadrunner.
Mammals have coexisted with dinosaurs since the Triassic period, 230 million years ago, and later with their successors, birds. But there hasn't been much of a level playing field between mammals and dinosaurs. Prior to the non-avian dinosaurs being wiped out by an asteroid 66 million years ago, the majority of mammals were tiny creatures who lived in the shadow of enormous reptiles and fed on insects and seeds. The largest Mesozoic mammals were little bigger than badgers.
As a result, Repenomamus robustus was a mammal giant in its day. It was a carnivorous mammal that weighed around 10 pounds and belonged to a now extinct family that flourished in the Early Cretaceous.
The fact that Repenomamus enjoys eating dinosaur meat is not altogether unexpected. In the stomach of a fossilised Repenomamus mammal, researchers in 2005 found the small bones of a newborn Psittacosaurus, an early relative of herbivores like Triceratops. However, more fossils were required to determine whether Repenomamus aggressively pursued larger dinosaurs or merely savoured helpless tiny dinosaurs.
The new discovery was made at a fossil-rich location in the Liaoning Province of China, which is frequently referred to as the "Chinese Pompeii." Many different animals, including feathered dinosaurs and early tyrannosaurs, were buried in debris by the region's explosive volcanoes during the Early Cretaceous. This provided palaeontologists with in-depth images of this old environment and preserved many of the area's past inhabitants in three dimensions.
A local farmer discovered the fossilised scuffle used in the latest study in 2012, and palaeontologist Gang Han of China's Hainan Vocational University of Science and Technology quickly collected it. Han collaborated with colleagues in Canada to describe the amazing discovery.
Jordan Mallon, a palaeontologist at the Canadian Museum of Nature in Ontario and a research co-author, says, "When I was shown the fossil, my eyes just about popped out of my head."
Both skeletons are complete and are still engaged in a never-ending mortal struggle, with the exception of the tip of Repenomamus' tail. At first, Mallon thought, this was too wonderful to be true. Many of these frauds are straightforward, side-by-side juxtapositions that are not even close to as sophisticated as the entwined Repenomamus and Psittacosaurus skeletons.
However, certain fossil dealers in the area are known to piece together random bones to create dramatic set pieces. "We confirmed that the mammal does indeed plunge its left lower jaw into the rock to clench the ribs of the dinosaur," adds Mallon.