Titanophoneus potens

The "giant murderer"

The saber fanged Dinocephalians were the top predators during the Permian era. They belonged to a group called the Therapsids, which were reptiles, but with advanced mammalian anatomical  traits such as larger brains, heterodont (differentiated) teeth, and a more erect and therefore active posture. The  canine teeth and sharp incisors were very well developed while the molar teeth in the rest of the jaw were weak and underdeveloped to non-existent. These beasts were well adapted for biting into the thick hide of the plant eating Dicynodonts and Pariesaurs, and then probably bolting the chunks of meat down the throat quickly.

Titanophoneus was found in late Permian rocks from Tartarstan eastern Russia which are 253 million years old. These deposits are full of skeletons of the terrestrial tetrapod (four-legged) fauna for this time period. Titanophoneus was a more primitive form of Therapsid predator because of its short legs and semi-sprawling stance. Later species of Dinocephalians walked fully erect, which would have required a lot of energy, and would have generated a lot of body heat. Thus, it is widely believed that they were warm-blooded. Titanophoneus also has a longer lizard-like tail, which is a primitive feature on Therapsids. But the skull details show that it was evolving in the right direction: The temporal opening behind the eye socket was larger compared to earlier species, which gave an expanded  bulging area for the muscle masses that operated the jaws.

Massive glaciations occurred during the early Permian, which may have made the global climate much more variable than the previous carboniferous. Although these glacial events were largely over by Titanophoneus' time. There is some evidence to suggest that these animals had fur. This is more argument in favor of endothermy ( warm-bloodedness ) in the Therapsids. In this illustration I have added a mammal-style external ear, which is  purely artistic license - there is no physical evidence to support this idea.