A new European rodent from the middle Eocene of Spain, Zamoramys extraneus n. gen., n. sp., appears to be closely related to the middle Eocene chapattimyid rodents of Indo-Pakistan. This contradicts the generally accepted paleobiogeographic hypothesis of a Tethyian barrier between Europe and Asia isolating Europe during the middle Eocene. Because of this barrier, some authors have proposed that European and Asian rodents were not closely related, their similarity being the result of morphological convergence. Here monophyly has been tested, using the parsimony criterion, based on an analysis of dental characters (including discussing of homology and the validity of some characteristics). Our results indicate a phylogenetic relationship among the Asiatic Ctenodactyloidea, Zamoramys from Spain, and the European endemic Theridomyoidea. We also conclude from our analysis that theridomyoids and European ischyromyoids are probably not closely related phylogenetically. 

The description of new material of the Upper Eoœne of France, Southem Germany and Spain together with the restudy of the material described by Thaler (1966b) as Pairomys allows to confirm the validity of the genus Ectropomys up to know controversally discussed. As a consequence the subfamily Remyinae and Oltinomyinae can be defined precisely. The study of the dental characters shows that the Remyinae in fact belong to the Theridomyidae and represent a derived evolutionary unit within this family. The Oltinomyinae together with the Theridomyinae and Issiodoromyinae very probably form a monophyletic unit.