First known complete skulls of the scimitar-toothed catMachairodus aphanistus(Felidae, Carnivora) from the Spanish late Miocene site of Batallones-1

Abstract

We describe a sample of skulls, mandibles and isolated dentitions of Machairodus aphanistus from the Spanish late Vallesian (late Miocene) site of Batallones-1, near Madrid. This is the first time that the cranial morphology of this species has been seen in detail, and shows that late Vallesian M. aphanistus combined a relatively primitive cranial and mandibular morphology with very specialized upper canines, as flattened as in the later, cranially derived species M. giganteus. Cranio-mandibular adaptations for the canine shear-bite are incipient or non-existent, suggesting that the specialized canines of M. aphanistus were used within the context of a biting mechanism more similar to the canine bite of modern felids. Evolution of more extreme machairodont craniodental features in later members of the homotherin lineage converged with smilodontins but occurred independently of the initial development of derived saber-like canines. The high number of specimens, at least 14 individuals represented,...