First record of a diacodexeid artiodactyl in the middle Eocene Pondaung Formation (Myanmar)

摘要

A fragmentary maxilla referred to a new diacodexeid artiodactyl, Magwetherium burmense, n. gen. and sp., is described from Sabapondaung locality in the middle Eocene Pondaung Formation in Myanmar. Comparisons with other basal artiodactyls known in the Eocene of Asia, Europe, and North America reveal that this unexpected new taxon displays an unusual combination of derived and primitive features. Magwetherium further displays more morphological affinities with the diacodexeid Jiangsudon from the middle Eocene Shanghuang fissure fillings in eastern China than with any other Holarctic dichobunoids. This study also suggests that fossil remains from Pondaung recently described as indeterminate artiodactyls can likely be referred to dichobunids. The occurrence of a diacodexeid artiodactyl in Southeast Asia extends the fossil record of the family in this part of the continent, it represents the youngest representative of the family, and it further documents the adaptive radiation of diacodexeids in Asia during the Eocene.