Anteosaurinae is an extinct subfamily of

dinocephalia Dinocephalians (terrible heads) are a clade of large-bodied early therapsids that flourished in the Early and Middle Permian between 279.5 and 260 million years ago (Ma), but became extinct during the Capitanian mass extinction event. Dinoceph ...

therapsid Therapsida is a major group of eupelycosaurian synapsids that includes mammals, their ancestors and relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more ...

s. It is one of two subfamilies in the family Anteosauridae, the other being

Syodontinae Syodontinae is a group of dinocephalian therapsids. It is one of two subfamilies in the family Anteosauridae, the other being Anteosaurinae. They are known from the Middle Permian Period of what is now Russia and South Africa. One of the best ...

Description

These are very specialized, very large

anteosaur Anteosaurs are a group of large, primitive carnivorous dinocephalian therapsids with large canines and incisors and short limbs, that are known from the Middle Permian of South Africa, Russia, China, and Brazil. Some grew very large, with skulls ...

s. The postcanine teeth are further reduced. Deepening of the postorbital region of the skull (behind the eyes) produced a larger temporal opening, indicating more muscle mass. The boss on the angular (rear of the jaw) has become very prominent, again, another sign of powerful jaw muscles. These huge animals were clearly formidable predators. In the Anteosaurinae, pachyostosis is taken to extremes. The dorsal (upper) surface of the nasal, frontal, and postfrontals (around and between/above the eyes) is thickened and rugose in the same manner as the

tapinocephalid Tapinocephalidae was an advanced family (biology), family of tapinocephalians. It is defined as the clade containing ''Ulemosaurus'', ''Tapinocaninus'', and the Tapinocephalinae. They are known from both Russia and South Africa. In all probabilit ...

s. Nevertheless these animals are too specialized and too late in time to have been the ancestors of the herbivorous tapinocephalids, so these characteristics evolved independently. Boonstra notes that the hip joint and the femur of ''

Anteosaurus ''Anteosaurus'' (meaning "Antaeus reptile") is an extinct genus of large carnivorous dinocephalian synapsid. It lived at the end of the Guadalupian (= Middle Permian) during the Capitanian stage, about 265 to 260 million years ago in what is now ...

'' is comparable with those of the

crocodile Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to inclu ...

and that these animals may have had a crawling habit. In view of the carnivorous dentition, he believes them to have been slinking predators.

Classification

Below is a

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

showing

syodontine Syodontinae is a group of dinocephalian therapsids. It is one of two subfamilies in the family Anteosauridae, the other being Anteosaurinae. They are known from the Middle Permian Period of what is now Russia and South Africa. One of the best kn ...

relationships from a 2012

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

study of anteosaurians:

References

External links

Anteosauridae
at Palaeos {{Taxonbar, from=Q4771298 Anteosaurs Guadalupian first appearances Guadalupian extinctions Prehistoric animal subfamilies