Such tiny bones for such an amazing discovery!
Our oldest #evolutionary ancestor was no bigger than a shrew and built for climbing through trees. The bones of this tiny creature were found in Montana at a place called Purgatory Hill, therefore this early primate is named Purgatorius, and dates to 65 million years ago.
Read more at: 
http://westerndigs.org/bones-discovered-in-montana-are-of-the-worlds-earliest-primate-study-finds/