Barnum Brown was prospecting along areas of Pondaung Sandstone in Myanmar in 1923, he discovered a mandible with three teeth (Amphipithecus mogaungensis). He did not recognise the significance of his find until 14 years later, when Edwin H. Colbert identified the fossil as a new species of primate and the earliest known simian.

In May 2005, the discovery of dozens of new primate fossils,