This ‘crazy beast’ who lived with dinosaurs was different from other creatures

Scientists say they are baffled by the eerie appearance of a 66-million-year-old opossum-sized mammal nicknamed Adalatherium – which translates to ‘mad beast’.

“Knowing what we know about the skeletal anatomy of all living and extinct mammals, it’s hard to imagine that a mammal like Adalatherium could have evolved,” David Krause, of the Denver Museum of Nature and Science, said in a statement. “It bends and even breaks a lot of rules.”

On Friday, Krause, along with Simone Hoffmann of the New York Institute of Technology and their team, published a 234-page study of a fossilized Adalatherium skeleton unearthed in 1999. They first announced the results of 20 years of research in April. , in Nature magazine. Today’s in-depth article appears in the Society of Vertebrate Paleontology Memoir Series, an annual publication that takes an in-depth look at the most important vertebrate fossils.

Researchers describe the creature as having had muscular hind limbs like those of a crocodile, powerful front legs, front teeth resembling rabbits, and strange rear teeth that do not look completely like any other known mammal. It also had an unusual space between the bones at the top of its muzzle and more trunk vertebrae than most other mammals.

The Adalatherium was a “giant” compared to the mouse-sized mammals that lived alongside dinosaurs during the Cretaceous Period (145.5 million years ago to 66 million years ago). He lived in Madagascar and belongs to an extinct group of mammals called gondwanatherians, first discovered in the 1980s.

The bizarre appearance of the ancient animal causes scientists to scratch their heads. Its muscular legs and large claws on the hind legs imply that it was a powerful digger, but its front legs were less muscular, which could mean that the creature was a fast runner.

Its forelimbs were tucked under the body like those of most mammals, but its hind limbs were more extended, like those of a lizard. Then there are those teeth, which suggest a herbivore but still weird. And scientists have yet to figure out the purpose of the hole in the top of the muzzle.

“Adalatherium is just weird,” Hoffmann said in the statement. “Trying to figure out how he moved, for example, was a challenge because his front-end tells us a completely different story than his back-end.”

However, this “mad beast” could help scientists tell a clearer story about how mammals, or at least some of them, developed.

“Adalatherium is an important piece in a very large puzzle of early mammalian evolution in the southern hemisphere,” Hoffmann said, “a piece in which most of the other pieces are still missing.”