The locality of Thermopigi in northern Greece has yielded a well-preserved skull of Ancylotherium pentelicum, among a rich collection of late Miocene mammals. It is the most complete Ancylotherium skull ever reported, and lack of crushing makes it especially valuable. Its most remarkable feature is the inflation of the frontal bone, which is strongly reminiscent of the dome of the North American Tylocephalonyx Coombs, 1979, although the degree of inflation is weaker than in that genus. An analysis of some characters found in the Miocene Schizotheriinae leads to the conclusion that Ancylotherium is more likely to be closely related to other Eurasian and African members of this subfamily than to Tylocephalonyx, and that the domes evolved in parallel.