A New Thaumastocyoninae (Amphicyonidae, Carnivora) from the Early Miocene of Tuchořice, the Czech Republic

Abstract New Amphicyonidae fossil remains from the early Miocene site of Tuchořice (the Czech Republic) confirm the presence of a new Thaumastocyoninae taxon: Peignecyon felinoides n. gen. et n. sp. It is characterized by a peculiar combination of plesiomorphic and derived morphological traits. The new genus can be defined by a long and sharp mandible diastema, loss of mesial premolars (p2–p3), p4 with an inclined distally high main cuspid, moderate sectorial carnassial teeth, m1 with relict metaconid, and talonid and trigonid of similar width, and reduced M2 and m2. In the phylogenetic analysis the Thaumastocyoninae form a monophyletic group characterized by the start of the m2/M2 reduction, still moderate in Crassidia intermedia (von Meyer, 1849), but remarkable in the other species of the clade. Peignecyon felinoides already shows the advanced features defining the Thaumastocyoninae, and constitutes the sister group of the most specialized genera Tomocyon Viret, 1929b and Thaumastocyon Sthelin et Helbing, 1925. Consequently, it can be considered an excellent link between this group and the more primitive members of the tribe Ysengrini (Ysengrinia Ginsburg, 1966 and Crassidia Heizmannn et Kordikova, 2000). Peignecyon felinoides shows that the trend towards hypercarnivory had already emerged in the European early Miocene fauna, thus helping to understand the complex evolution of the Amphicyonidae during the Miocene.