New Glires materials from the East Mesa, Erlian Basin (Nei Mongol, China)

Abstract

East Mesa, an Eocene locality situated east of the Shara Murun River in the Erlian Basin, is characterized by basal lower red mudstones. However, a distinct depositional hiatus has been observed in these red mudstones, leading to their division into layers 1 and 2. Excitingly, recent discoveries respectively in layers 1 and 2 of the lower red mudstones at the East Mesa include new Glires (Gomphos sp.) and rodents such as Asiomys dawsoni, Gobiocylindrodon cf. G. ulausuensis, and Yuomys sp., marking their first occurrences within these horizons. A comparative analysis of small mammal faunas suggests that layer 1 may correspond to the Arshantan age, while layer 2 indicates a late Irdinmanhan age based on the combination of taxa found.