Temporal range: Capitanian, 266–260Ma
|Life restoration of Anteosaurus magnificus|
Anteosaurus (meaning "previous or early reptile") is the name given to an extinct genus of large carnivorous synapsid. It lived during the Capitanian epoch of the Middle Permian (266-260 million years ago) in what is now South Africa. They became extinct by the middle Late Permian.
Anteosaurus was a semiaquatic synapsid with a long tail and weak limbs, which indicate a lifestyle including water, much like that of a crocodile. Anteosaurus was estimated to be over 5 metres (16 ft) long. Its most notable characteristic is its tall, narrow skull, which is 80 centimetres (31 in) long. The size of the skull is used to determine the age of a fossil. The teeth are another identifying characteristic of Anteosaurus. The teeth on the roof of the mouth are enlarged and confined in a cluster near the outer tooth row. The "normal teeth" include the anterior, canine and cheek teeth. A prominent feature of the dinocephalians is the ledge on the anterior teeth. The canine teeth are big, and there are usually about 10 cheek teeth present. The front of the mouth curves up due to the premaxillary bone of the upper jaw. Paleontologists believe the presence of pachyostosis (thickening of the roof of the head) indicates a "head-butting" behavior of these dinocephalians, probably for protecting territory and fighting over a mate. This feature indicates that they were active on land as well.
The skull of a young Anteosaurus was found in Eastern Cape Province, South Africa where many skull fragments have been discovered relating to the dinocephalians. While 4 other Anteosauridae were found in the Isheevo region, Anteosaurus was the only anteosaurid predator in the South African temperate zone.
The ancestors of early therapsids from the late Permian include Struthiocephalus and Tapinocaninus. These therapsids are classified by their skull pachyostosis, body size, and herbivory. Five other genera of Anteosauridae are related to Anteosaurus: Australosyodon, Micranteosaurus (considered a "young" anteosaurus because of its small size), Paranteosaurus, Sinophoneus and Titanophoneus. There are 16 well-preserved skulls of Anteosaurus, 10 of which have been named as species of Anteosaurus, and are distinguished by their skull size and shape, number size and shape of teeth. The primitive skull and canine teeth are a distinctive characteristic of the Anteosaurus, which were passed on to its later descendants such as the Titanosuchidae, many of which changed their dietary habits to become omnivores or herbivores. The giant Anteosaurus is known to have existed at the same time that Titanophoneus and Doliosauriscus dominated in the Isheevo region. The family Anteosauridae replaced the Eotitanosuchidae, but were replaced in turn by large gorgonopsids.
- van Valkenburgh, Blaire; Jenkins, Ian (2002). "Evolutionary Patterns in the History of Permo-Triassic and Cenozoic synapsid predators". Paleontological Society Papers 8: 267–288.