Anteosaurus
Encyclopedia
Anteosaurus is the name given to an extinct genus of large carnivorous synapsid
Synapsid
Synapsids are a group of animals that includes mammals and everything more closely related to mammals than to other living amniotes. They are easily separated from other amniotes by having an opening low in the skull roof behind each eye, leaving a bony arch beneath each, accounting for their name...

. It lived during the Capitanian
Capitanian
In the geologic timescale, the Capitanian is an age or stage of the Permian. It is also the uppermost or latest of three subdivisions of the Guadalupian epoch or series. The Capitanian lasted between and...

 epoch of the Middle Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

 (266-260 million years ago) in what is now South Africa. They became extinct by the middle Late Permian.

Anteosaurus was a semi aquatic synapsid with a long tail and weak limbs, which indicate a lifestyle including water, much like that of a crocodile. Anteosaurus weighed approximately 500-600 kg and was around 5-6 m long. Its most notable characteristic is its tall, narrow skull, which is 80 cm 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
Pachyostosis
Pachyostosis is a condition in vertebrate animals in which the bones experience a thickening, resulting in unusually solid bone structure with little to no marrow. It occurs in both terrestrial and aquatic vertebrates, such as manatees and dugongs, plesiosaurs, and members of the Dinocephalia...

 (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.

Discovery

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, the Anteosaurus was the only Anteosauridae
Anteosauridae
The Anteosauridae or Anteosaurinae are a family or subfamily of very large carnivorous Dinocephalia that are known from the Middle Permian of Russia and South Africa...

 predator in the South African temperate zone.

Related species

The ancestors of Early Therapsids from the late Permian include Strathiocephalus and Tapinocaninus
Tapinocaninus
Tapinocaninus is an extinct genus of the family Tapinocephalidae....

. These Therapsids are classified by their skull pachyostosis
Pachyostosis
Pachyostosis is a condition in vertebrate animals in which the bones experience a thickening, resulting in unusually solid bone structure with little to no marrow. It occurs in both terrestrial and aquatic vertebrates, such as manatees and dugongs, plesiosaurs, and members of the Dinocephalia...

, body size, and herbivory. There are six other genera of the Tapinocephalus
Tapinocephalus
Tapinocephalus is a genus of large herbivorous dinocephalian that lived during the Middle Permian Period. These stocky, barrel-bodied animals were characterised by a massive bony skull roof and short weak snout...

 which are related to Anteosaurus
Anteosaurus
Anteosaurus is the name given to an extinct genus of large carnivorous synapsid. It lived during the Capitanian epoch of the Middle Permian in what is now South Africa...

: Eccasaurus, Titanognathus
Titanognathus
Titanognathus is an extinct genus of non-mammalian synapsid.-References:*...

, Dinosuchus
Dinosuchus
Not to be confused with Deinosuchus, a North American alligatoroid.Dinosuchus is a problematic genus of extinct alligatorid crocodylomorph. It was very large compared to other alligatorids, save for the giant caiman Purussaurus and its closest relatives...

, Micranteosaurus
Micranteosaurus
Micranteosaurus is an extinct genus of non-mammalian synapsid.-References:*...

(considered a "young" anteosaurus because of its small size) and Pseudanteosaurus
Pseudanteosaurus
Pseudanteosaurus is an extinct genus of non-mammalian synapsid.-References:*...

. 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
Titanosuchidae
The titanosuchids were carnivorous to omnivorous tapinocephalid dinocephalians. As with other tapinocephalids, they had thick-skulls probably for head-butting. They appeared in the Middle Permian. They had large canine teeth, and their incisors were very strong...

, which replaced most eating habits into herbivory.
The giant Anteosaurus is known to have existed at the same time that the Titanophoneus
Titanophoneus
Titanophoneus potens was a carnivorous Therapsid of the Dinocephalia group related to the Estemmenosuchidae, but living 5 million years later than Estemmenosuchus, during the Late Permian. Remains of this animal have been found at Isheevo in RussiaAn adult skull would have reached 80 cm with a...

and Doliosauriscus
Doliosauriscus
Doliosauriscus is an extinct genus of dinocephalian therapsid that lived in Russia during the mid-Permian Period. It was a large carnivore, its skull measuring 53 centimeters long.thumb|left|200px...

dominated in the Isheevo region.
The Anteosauridae family replaced the Eotitanosuchidae
Eotitanosuchidae
Eotitanosuchidae is an extinct family of biarmosuchian therapsids. Philosophy.-References:*...

, but they (the Anteosauridae) were replaced by large Gorgonopsids.

Sources

  • http://www.palaeos.com/Vertebrates/Units/400Therapsida/500.html#Anteosaurus
  • http://www.kheper.net/evolution/therapsida/Brithopodidae.html
  • http://www.palaeos.org/Anteosaurus
  • http://eprints.ru.ac.za/557/
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