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 anrhracotheriid has been discovered in th e middle Eocene locality of Kyawdaw in the Pondaung Formation (Myanmar). Th is specimen represents a primitive new species (Siamotherium pondaungensis, sp. nov.), possibly ancestral to Siamotherium krabiense from the late Eoce ne of Krabi (Thailand). The occurrence of S. pondaungensis in Myanmar sugge sts that Krabi is younger than the localities of the Pondaung Formation, an d it further supports the role that southern Asia played in the origin and evolution of several groups of mammals.