Presenting yet another diversion from news and views on the novel coronavirus (Covid-19) pandemic, the life and times of a ‘crazy beast’ which lived 66mn years ago in isolation on the island of Madagascar has suddenly come into research spotlight. The specimen represents a poorly understood group of mammals called Gondwanatherians, but this creature had lots of unique features.
The badger-like animal, which belongs to a new genus and species called Adalatherium hui, is named after researcher Yaoming Hu who helped analyse the fossil but passed away in 2008. The name Adalatherium is translated from the Malagasy and Greek languages and means ‘crazy beast’. 
According to a paper in the journal Nature on Friday, the cat-sized mammal lived among some of the last dinosaurs to walk the Earth. Though the fossil specimen was found in 1999 in north-west Madagascar’s Mahajanga Basin, a detailed study has been completed only now. It is the most complete and best-preserved mammal find from Gondwana - an ancient southern supercontinent that once included India and Africa - during the time of the dinosaurs. However, when this mammal was alive, Gondwana was breaking up, and Madagascar had already become an island.
The discovery of the fossil challenges previous assumptions that mammals were generally very small - the size of mice - at this point in their evolutionary history. Researchers say this individual animal weighed 3kg and had not reached its full adult size. It had a large collection of nerves in the snout, making this area extremely sensitive - a feature frequently seen in burrowing animals.
It is estimated that the uniqueness of the species comes from evolving in isolation on the island of Madagascar for at least 20mn years. The ‘crazy beast’ had a hole-filled skull, which probably made room for lots of nerves and blood vessels leading to its nose. Its teeth were shaped differently from those of any other mammal, and it had more vertebrae than its contemporaries. Its stance was equally strange: It held its front limbs straight down like any other modern mammal, but its rear limbs splayed outwards like an alligator’s.
The creature’s weirdness is attributed to the evolution on an island. Madagascar separated from other landmasses around 88mn years ago, so any animals that were on the island evolved in isolation. There’s a theory that isolation on islands causes smaller species to grow larger because of a lack of predators, larger species to grow smaller due to a lack of resources, and all species to develop weird features. Though researchers say there are plenty such examples, there are only a few for ancient mammals.
Dr John Wible, the curator of mammals at the Carnegie Museum of History was part of a team that announced the discovery of the ‘crazy beast’ fossil mammal skeleton, describes it as “an unprecedented opportunity to reconstruct the anatomy and lifeway of a Gondwanatherian and to place it on the mammal tree of life.” Dr David Krause, senior curator of vertebrate palaeontology at the Denver Museum of Nature and Science, and the research leader, stated that the discovery “bends and even breaks lots of rules.”