Andrey Atuchin
Scientists say they are puzzled by the strange appearance of a 66-million-year-old mammal called Adalatherium – which translates to “crazy 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. “He 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 the journal Nature. Today’s in-depth work appears in the Society of Vertebrate Paleontology Memoir Series, an annual publication that examines in depth the most important vertebrate fossils.
Researchers describe the creature as having muscular hind limbs, such as the crocodile’s strong front legs, bunny front teeth, and strange hind teeth, which closely resemble those of any other known mammal. It also had an unusual space between the bones at the tip of its snout and more vertebrae in the trunk than most other mammals.
Adalatherium was a “giant” compared to mouse-sized mammals, which lived with dinosaurs during the Cretaceous (145.5 million years 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 makes scientists scratch their heads. His muscular legs and large claws on his hind legs imply that he was a powerful excavator, but his front legs were less courageous, which could mean that the creature was a fast runner.
A closer look at an Adalatherium skeleton.
Simone Hoffmann and Kathrine Pan
The forelegs were hidden under the body like those of most mammals, but the hind limbs were wider, like those of a lizard. Then there are those teeth, which suggest a herbivore, but remain bizarre. And scientists have not yet discovered the purpose of the hole in the tip of the snout.
“Adalatherium is simply strange,” Hoffmann said in a statement. “Trying to find out how it moved, for example, was a challenge, because our front-end tells us a completely different story than its back-end.”
However, such nonsense aside, this “crazy beast” could help scientists finally tell a clearer story about how mammals evolved, or at least some of them.
“Adalatherium is an important piece in a very large puzzle about the early evolution of mammals in the southern hemisphere,” said Hoffmann, “one in which most of the other pieces are still missing.”