A research team has recently published the discovery of a nearly complete and well-preserved mammalian skeletal fossil in Madagascar dated 66 million years. Their research was published last April 29 in the Nature journal and funded by the National Geographic Society and the National Science Foundation.

The fossil was found in the northwestern area of the country and has been determined to come from the Mesozoic Era, existing alongside the dinosaurs, which occurred roughly 250 to 66 million years in the past. It is currently the most complete Mesozoic mammalian fossil discovered from the Earth's southern hemisphere.

The scientists named this new and bizarre mammalian species Adalatherium hui, meaning "crazy beast" in Greek and Malagasy. The species name "hui" gives honor to paleontologist Yaoming Hu whose specialization is early mammals.

The new species, at first glance and to the untrained observer, looks similar to a badger the size of a house cat. To the researchers who discovered the mammal, however, it is a very odd animal--odder than most creatures they know.

The Denver Museum of Nature and Science curator and lead author David Krause says that with what scientists know regarding the skeletal anatomy of mammals, both extant and extinct, the evolution of Adalatherium would have been improbable at best; the animal bends and breaks many rules.

The Crazy Beast and Its Mysterious Ancestry

The Mesozoic fossil record contains few mammalian fossils. This particular creature has a unique anatomical structure. One of its peculiar characteristics is its teeth, which are very different from those of other mammals. Thus its teeth do not really help in establishing its ancestry.

Another aspect is its strange vertebral column, which is more numerous than modern mammals.

Thirdly, its leg bones are strangely curved. New York Institute of Technology's Simone Hoffmann, co-author of the study, says that it was almost impossible for the researchers to determine how the animal moved. For example, the apparent movement of the front limbs based on their shape does not seem to agree with that of the hind limbs.

Additionally, the animal is unusually bigger than the mammals known to have co-existed with the dinosaurs, which did not grow larger than the size of modern mice.

The odd nature of animal and plant species that evolved in islands is not surprising. There are different evolutionary dynamics at work in such isolated areas, with their unique nature and processes.

A. hui belongs to a poorly known group of extinct mammalian creatures known as "gondwanatherians." The name is derived from Gondwana or Gondwanaland, the ancient southern supercontinent where Madagascar belonged. During Gondwana's existence, Madagascar was situated between what is currently the modern Indian subcontinent and today's African continent.

The plants and animals in Madagascar have been isolated from other ecosystems by millions of years; this spurred their unique evolutionary path. The mammalian ancestors of A. hui have evolved separately in Madagascar for over 20 million years.

University of Louisville paleontologist and study co-author Guillermo Rougier stated that places that have been isolated for a long time produce unique biological specimens. Here, evolution can take unexpected shapes and forms because of their isolation.

A. hui joins many strange species, both modern and extinct that called Madagascar their home. These include Beelzebufo ampinga, a predatory armored frog as big as a beach ball; Simosuchus, a vegetarian, pug-nosed crocodile; and Masiakasaurus, a buck-toothed species of dinosaur.

The research team believes that A. hui could be a key to science's understanding of early mammalian evolution in Gondwana. Discovering more extinct species will provide a better picture of their evolution.