Rodents from the Middle Oligocene of Turkish Thrace

Associations of Middle Oligocene rodent teeth are described from five localities in the Lignite-Sandstone Formation of the Ergene basin. The Muroidea are the most abundant as well as the most diverse group in these associations. In rodent faunas of Western Europe the Theridomyoidea dominate. So far representatives of the Theridomyidae have not been found in Thrace and do not seem to have reached Turkey. In addition to seven new (sub)species four new (sub)genera of the Muroidea are defined: Trakymys, Edirnella, Lignite!!a and Kerosinia. The classification of the European Paleogene representatives of this superfamily is discussed and revised. It is concluded that raising a number of taxonomic entities within the Muroidea to a higher rank in the hierachy is in better accordance with our present knowledge of the group than the widely followed classification of Mein and Freudenthal (1971), who include all Tertiary hamsters in one family: the Cricetidae. In addition to Muroidea the rodent associations from Thrace contain teeth of members of the families Eomyidae, Gliridae, Pseudosciuridae, Castoridae and Petauristidae in limited numbers. New species of each of the genera Eomys, Bransatoglis and Glis are described. The faunal details suggest that the five localities correspond to successive levels during an Oligocene time span of approximately one My. Two major zones are apparent but there seem to be possibilities to make a further (sub)zonal subdivision. Our faunas are correlated with part of the MP 23-27 interval of the European standard zonation. The large numbers of Melissiodontidae and Anthracotheriidae suggest vegetated wetland biotopes throughout the investigated interval.