The Therapsids

Dinocephalian World
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"there shall be gnashing of teeth" and Working of Jaws
Of course, it's not enough to stride about.  The animals which process their enviroment most efficiently tend to be masters of that enviroment. And dinocephalians had pearly whites like no one else. Dinocephalian teeth weren't the simple stabbing points of their pelycosaur ancestors. Dinocephalian predators nipped much like the gorgonopsians. However, the teeth of the plant-eating dinocephalians [left] were much more complex. Each tooth featured a projecting, ledge-like 'heel'. When the jaw was clenched, the teeth interlaced like the fingers of clasped hands. The food caught between the blunt point of one tooth and the heel of an opposing tooth would be sliced, ground up, or crushed.

Ulemosaurus svijagensis with Titanophoneus potens in hot pursuit  —  top left
Fleeing Ulemosaurus ('reptile from the Ulema River'  —  skull 45cm) shows off a lovely set of all-purpose dinocephalian gnashers.  The pursuing pair of Titano- phoneus ('the giant murderer' — skull 43cm) have less specialized teeth. Titano- phoneus was originally thought to be a weak-limbed fish-eater. Those big canine teeth suggest a diet more in keeping with its rather blood-thirsty name.

Of course bite-force is as important as tooth-type.  What set the dinocephalians apart from their pelycosaur ancestors was their jaw-closing muscles.  The main muscle, the external adductor (blue — on the side of the head), was greatly enlarged and it was assisted, once the jaws were closed, by an entirely new group of jaw-closing muscles (light yellow) which fanned out, attaching to the animal's neck ribs and shoulder girdle.

Dinocephalian World
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