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- Adalatherium hui, which translates into Malagasy and Greek as “mad beast”, was discovered by studying a 66 million year old fossil from Madagascar.
- One of the earliest mammal species, it has a peculiar anatomy and a mosaic of characteristics that is different from other mammals, from its peculiar teeth to its curved bones.
- It is also unusually large, about the size of a domestic cat, compared to other mammals that coexisted with dinosaurs, which were no bigger than today’s mice.
- The researchers believe that it is key to understanding the early evolution of mammals in the southern hemisphere.
A 66 million-year-old fossil has allowed scientists to describe a strange new species of mammal that lived in Madagascar during the time of the dinosaurs. They have baptized him Adalatherium hui, which in Malagasy and Greek translates to “crazy beast”. The “hui” is a nod to Yaoming Hu, a paleontologist who specialized in early mammals.
At first glance, it looks like a badger the size of a domestic cat; but for the scientists who discovered it, A. hui it is nothing less than the “weirdest weirdo” creatures. “Knowing what we know about the skeletal anatomy of all living and extinct mammals, it is difficult to imagine that a mammal Adalatherium it could have evolved; it bends and even breaks many rules, “lead researcher David Krause, curator of the Denver Museum of Nature and Science, said in a statement.
The fossil record is sparsely populated with fossils of mammals from the Mesozoic era. The team was lucky and discovered a well-preserved, almost complete skeleton in northwestern Madagascar. It turned out to be the most complete fossil of all Mesozoic mammals found in the southern hemisphere. The Mesozoic, known as the age of the dinosaurs, lasted from approximately 252 million years ago to approximately 66 million years ago.
What makes the creature exceptional is its anatomical structure, which is a unique mosaic of features. For one thing, their peculiar teeth give little indication of their ancestry because they are nothing like those found in other mammals. On the other hand, its spinal column has more vertebrae than any of the contemporary mammals. Then there are the oddly curved leg bones.
“Trying to figure out how it moved is almost impossible because, for example, its front tells a different story than its rear,” said Simone Hoffmann of the New York Institute of Technology, co-author of the study.
It is also unusually large compared to other mammals that coexisted with dinosaurs, which were no bigger than today’s mice.
The discovery of strangely sized animals and plants is not unusual on the islands. A. hui It is a member of the Gondwanatherians, a poorly understood group of extinct mammals that lived on the Gondwana supercontinent. On this massive landmass, Madagascar lay between what would later become Africa and the Indian subcontinent.
Madagascar separated from the Indian plate about 88 million years ago, and thus became the oldest island on the planet. The wild inhabitants of Madagascar have evolved in isolation for millions of years, which explains the strangeness of many of the species found here. The branch of mammals that gave rise to A. hui It evolved unhindered for over 20 million years on the island.
“Long, isolated places produce very unique results in biology,” Guillermo Rougier, a paleontologist at the University of Louisville and co-author of the article, said in a statement. “These fossils remind us of the unexpected shapes and forms that evolution can take over long periods of time in an isolated location.”
A. hui It is just the latest addition to the pantheon of rare species that live and have lived in Madagascar. The island is home to who’s who of the world’s strangest creatures. Krause and his team have only discovered several: from an armored predatory frog (Beelzebufo ampinga) the size of a beach ball, a type of vegetarian pug-nosed crocodile (Simosuchus spp.), and even a rabbit-toothed dinosaur (Masiakasaurus spp.).
The team was stumped A. hui specimen for over a decade, trying to place it in the evolutionary history of mammals. They say they believe it is key to understanding the early evolution of mammals in the southern hemisphere. However, very little is known about the other fauna that existed at the dawn of the emergence of mammals. The discovery of stranger species should give a clearer picture of the early evolution of mammals.
The research was funded by the National Science Foundation and the National Geographic Society, and the article was published April 29 in the journal. Nature.
Citation:
Krause, D. W., Hoffmann, S., Hu, Y., Wible, J. R., Rougier, G. W., Kirk, E. C., … Rahantarisoa, L. J. (2020). The skeleton of a Cretaceous mammal from Madagascar reflects long-term insularity. Nature. doi: 10.1038 / s41586-020-2234-8
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(Banner image: A realistic reconstruction of Adalatherium hui. Image courtesy: Denver Museum of Nature and Science / Andrey Atuchin)
