Scientists have discovered an exquisitely preserved ancient primate fossil that they believe forms a crucial "missing link" between our own evolutionary branch of life and the rest of the animal kingdom.

The 47m-year-old primate – named Ida – has been hailed as the fossil equivalent of a "Rosetta Stone" for understanding the critical early stages of primate evolution.

"This little creature is going to show us our connection with the rest of all the mammals; with cows and sheep, and elephants and anteaters," said Sir David Attenborough who is narrating a BBC documentary on the find. "The more you look at Ida, the more you can see, as it were, the primate in embryo."

"It is really delightful and exciting and appropriate that 150 years after Darwin first tentatively put forward the proposition that human beings were part of the rest of animal life, that here at last we have the link which connects us directly ... Darwin would have been thrilled."