A mouse-sized fossil from China has provided remarkable new insights into the origin of primates.
At 55 million years old, it represents the earliest known member of this broad group of animals that includes humans.
Scientists have called the diminutive creature Archicebus, which roughly translates as "ancient monkey."
Chris Beard, curator of vertebrate paleontology at the Carnegie Museum of Natural History in Pittsburgh says the "ancient monkey" seems to be the earliest and most primitive known relative of the tarsiers.
Tarsiers are related to anthropoids, the primates that include monkeys, apes and humans.