Remains of the oldest ancestor of the most evolutionarily successful and long-lived mammal lineage have just been unearthed in China, according to a new study.
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, according to the paper, published in the journal Science.
PHOTOS: Ugly Animals That Need Saving Too: Photos
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.
"The later multituberculates of the Cretaceous and the Paleocene are extremely functionally diverse: Some could jump, some could burrow, others could climb trees and many more lived on the ground," explained Zhe-Xi Luo, a co-author of the paper. "The tree-climbing multituberculates and the jumping multituberculates had the most interesting ankle bones, capable of ‘hyper-back-rotation' of the hind feet."