Cynognathus

Cynognathus is an extinct genus of large-bodied cynodontian therapsids that lived in the Middle Triassic. It is known from a single species, Cynognathus crateronotus. Cynognathus was a predator closely related to mammals and had a southern hemispheric distribution. Fossils have so far been recovered from South Africa, Argentina, Antarctica, and Namibia.

== Description == left|thumb|Life reconstruction of Cynognathus crateronotus Cynognathus was a heavily built animal, and measured around in snout-to-vent body length and up to in total length. It was estimated to have weighed , to possibly . Cynognathus had a particularly large head, up to in length, with wide jaws and sharp teeth. Its hindlimbs were placed directly beneath the body. There has been controversy about whether the forelimbs were also held upright or sprawled outwards in a reptilian fashion, but recent studies suggest cynodonts typically held their front legs in a posture between these two extremes. A study of living mammals concluded that "upright posture" in mammals is a myth based on the posture of mammal species specialized for fast running, such as dogs, hares, and antelopes; modern mammals that are not specialized for running often hold their forelimbs in a semi-sprawled posture.