Anteosaurus

Anteosaurus is an extinct genus of large carnivorous dinocephalian synapsid. It lived at the end of the Guadalupian (Middle Permian) during the Capitanian age, about 265 to 260 million years ago, in what is now South Africa. It is mainly known from cranial remains and few postcranial bones. Measuring long and weighing about , Anteosaurus was the largest known carnivorous non-mammalian synapsid and the largest terrestrial predator of the Permian period. Occupying the top of the food chain in the Middle Permian, its skull, jaws and teeth show adaptations to capture large prey, such as giant titanosuchid and tapinocephalid dinocephalians and large pareiasaurs.

As in many other dinocephalians the cranial bones of Anteosaurus are pachyostosed (thickened), but to a lesser extent than those of tapinocephalid dinocephalians. In Anteosaurus, pachyostosis mainly occurs in the form of supraorbital protuberances, the horn- or boss-shaped prominences above the eyes. According to some paleontologists this structure would be implicated in intraspecific agonistic behaviour, including head-pushing, probably to compete with conspecifics over mating rights during the mating season. On the contrary, other scientists believe that these adaptations served to reduce cranial stresses on the bones of the skull during predation. Young Anteosaurus had fairly narrow and lean skulls, with the bones of their skull becoming progressively more pachyostosed as they grew, forming the characteristic robust skull roof of the genus.