London, August 26: A Mouse-like creature that scurried about in bushes and trees 160 million years ago gave rise to humans, scientists say.
The small, furry placental mammal lived in what is now north east China during the Jurassic era when dinosaurs ruled the Earth.
Its remarkably well preserved remains were dug up in the fossil- rich region of Liaoning Province which has also produced ancient evidence of feathered dinosaurs and primitive birds.
Named Juramaia sinensis, the fossil is the oldest ever found of a group of animals called the eutherians, or placentals, that give birth to live young.
They include cows, rats, monkeys, lions, tigers, dogs, horses, whales and, of course, our own group of mammals, the primates.
Juramaia, hairy and about the size of a mouse, provides fossil evidence of the date when eutherian mammals diverged from other mammals — metatherians whose descendants include marsupials such as kangaroos and monotremes such as the platypus.
Palaeontologist Zhe- Xi Luo, of the Carnegie Museum of Natural History in Pittsburgh, said: “ Juramaia, from 160 million years ago, is either a great- grandaunt, or a “ great- grandmother” of all placental mammals that are thriving today.
“ Analysis of the fossil skeleton indicates the animal was an agile creature with a powerful ability to climb. This may explain how it managed to survive during the age of the dinosaurs — by climbing and hiding in trees.” Describing the fossil in nature, the researchers say it represents a new milestone in mammal evolution that was reached 35 million years earlier than previously thought, filling an important gap in the record.
The name Juramaia sinensis means “ Jurassic mother from China.” The fossil has an incomplete skull, part of the skeleton, and, remarkably, impressions of residual soft tissues such as hair.
Most importantly, Juramaia’s complete teeth and forepaw bones enable paleontologists to pinpoint it is closer to living placentals on the mammalian family tree than to the pouched marsupials, such as kangaroos.