'Crazy Beast': Newly-Identified Prehistoric Mammal Has Features Never Seen Before

DENVER (CBS4) -- A new, prehistoric mammal has been discovered and it is described as "beyond bizarre." Paleontologists at the Denver Musuem of Nature and Science were part of a team of researchers that found the unusual mammal, whose name means "crazy beast."

Adalatherium hui lived alongside dinosaurs in the Late Cretaceous period -- approximately 66 million years ago -- on the island now known as Madagascar.

Experts say it had several unique features:

1. It has primitive features in its snout region (a septomaxilla bone) that hadn't been seen for a hundred million years in the lineage leading to modern mammals.
2. It had more holes (foramina) on its face than any known mammal, holes that served as passageways for nerves and blood vessels supplying a very sensitive snout that was covered with whiskers.
3. There is one very large hole on the top of its snout for which there is just no parallel in any known mammal, living or extinct.
4. The teeth of Adalatherium are vastly different in construction than any known mammal.
5. Its backbone had more vertebrae than any Mesozoic mammal and one of its leg bones was strangely curved.

Paleontologists say Adalatherium was a plant-eater that was capable of walking and running, and probably digging. It weighed about 6.8 pounds and was about the size of a living Virginia opossum or ring-tailed lemur.

It was likely preyed on by at least two meat-eating dinosaurs (Majungasaurus and Masiakasaurus) and two big crocodiles (Majungasuchus and Miadanasuchus). Another potential predator was the constrictor snake Madtsoia madagascariensis; which was 25-feet long and weighed over 100 pounds. It is the largest snake known from the entire Mesozoic of the world.

Museum officials say the discovery is remarkable for multiple reasons:

1. It is the most complete skeleton of any mammal from the entire Mesozoic period of the southern hemisphere. It is the only specimen of Adalatherium ever found.
2. About the size of an opossum, it is very large for a mammal that lived alongside dinosaurs. Anything larger than a mouse is extraordinary for this time period.
3. It is the first Mesozoic record of a mammal that confirms evolution on islands led to the development of features not found in mainland species (e.g., bizarre teeth, more vertebrae, and more holes in the skull than other mammals).

The specimen was dug up in Madagascar in 1999 and Dr. David Krause, senior curator of vertebrate paleontology at the Denver Museum of Nature and Science, has been studying it ever since.

In:
• Denver Museum of Nature and Science