Scientists have discovered a "crazy beast" mammal which lived alongside dinosaurs on Madagascar approximately 66 million years ago.

It was about the size of a modern cat or an opossum, according to researchers at Stony Brook University in the US, and the skeleton is the most complete for any mammal ever discovered from this era in the southern hemisphere.

The animal is also surprisingly large for mammals of its time, which were believed to be about the size of mice, and is expected to have burrowed to hunt for food and avoid dinosaurs.

It is officially called Adalatherium hui, which literally translates from Malagasy - the national language of Madagascar - and Greek as "crazy beast" and was announced in the journal Nature.

Image: The animal would have been about the size of a cat. Pic: Nature

Professor David Krause said: "Knowing what we know about the skeletal anatomy of all living and extinct mammals, it is difficult to imagine that a mammal like Adalatherium could have evolved; it bends and even breaks a lot of rules."


Despite the reconstruction showing the crazy beast's appearance to be similar to a badger, scientists say the animal's skeleton is actually "outlandish" - with primitive features in its snout which haven't "been seen for a hundred million years" in modern mammals.

"Its nasal cavity exhibits an amazing mosaic of features, some of which are very standard for a mammal, but some that I've never seen in anything before," explained Dr James Rossie.

Adalatherium had more holes, or foramina, on its face than any known mammal - passageways through the skull for nerves and blood vessels for what must have been a sensitive snout,covered with whiskers.

And bizarrely there is one very large hole on the top of its snout for which the scientists say there is simply no parallel in any known mammal, living or extinct.

Its teeth are also unlikely anything ever seen before in a mammal, and it had more vertebrae in its back than any other mammal from the same period.

Image: Its skeleton was found on Madagascar. Pic: National Geographic Society/Maria Stenzel

The researchers believe that it would have evolved into such a strange creature thanks to how isolated Madagascar was from any other land, due to plate tectonics.

Separated from mainland populations, animals on the island had more than 20 million years to develop "many ludicrous features" according to Professor Krause.