Fossil of most successful mammal unearthed

Remains of the oldest ancestor of the most evolutionarily successful and long-lived mammal lineage have just been unearthed in China. The mammal — one of several creatures known as multituberculates — looked like a cross between a small rat and a chipmunk. It lived 160 million years ago during the Cretaceous era. This particular new species was Rugosodon eurasiaticus, which is the oldest known multituberculate. Its remains were found preserved in lake sediments, suggesting that it lived on the shores.