Symplokeomys zaysanicus is a new genus and species of eomyid rodent fr
om the upper part of the Aksyir Formation of the Zaysan Basin, eastern
Kazakhstan. The new taxon differs from other eomyids in having a comp
lex pattern of interconnecting lophules within the central basin of it
s cheek teeth. Other mammals from the Aksyir Formation indicate an Erg
ilian (late Eocene) age.