A new anthracotheriid artiodactyl from Myanmar, and the relative ages of the Eocene anthropoid primate-bearing localities of Thailand (Krabi) and Myanmar (Pondaung)

A fragmentary maxillar of a small anthracotheriid has been discovered in the middle Eocene locality of Kyawdaw in the Pondaung Formation (Myanmar). This specimen represents a primitive new species (Siamotherium pondaungensis, sp. nov.), possibly ancestral to Siamotherium krabiense from the late Eocene of Krabi (Thailand). The occurrence of S. pondaungensis in Myanmar suggests that Krabi is younger than the localities of the Pondaung Formation, and it further supports the role that southern Asia played in the origin and evolution of several groups of mammals.