Mordax

The giant burdles, brutes, have been usurped now as a large foxtrotter predator now sits at the top of northern Serinaustra's food chain by 280 million years PE. What foxtrotters lack in the precise stability of quadruped birds like brutes, these tripedal tribbetheres can counter in their superior intellect and formidable toothy jaws that ultimately make them more efficient predators. But even now, they are not unrivaled, as skuorcs have reached Serinaustra and begun evolving into larger carnivorous forms too - and unlike either burdles (constrained by their shoulder anatomy) and foxtrotters limited in size by their single hind leg, they have few anatomical limits to their form.

But the mordax, weighing as much as a grizzly bear and standing as tall on all threes as a man on two, is a very competitive carnivore, both cunning and physically powerful. Long of leg and even graceful could be used to describe this tribbethere, which is a fast runner for its size, even over unstable and wet terrain. Its toes are long, splaying its weight in mud and bogs, letting it track prey into difficult places in the angled, murky depths of the swamp.

Though it is lean, the mordax is very strong, with a hugely muscular torso and a shoulder hump that powers a massive jaw forward to deliver absolutely catastrophic bites to other animals at a force of 5,000 pounds per square inch. Its jaws are mostly fused for strength, sacrificing mobility, and are powered by huge muscles that give its skull a crocodile-like profile. They are evolved to hold on slower, large and tenacious prey like grumplumps and bring them off their feet. While their hind teeth shear flesh when feeding and dagger-like middle ones hold tight on struggling prey, their front teeth slot neatly together, with a knife-like recumbent lower incisor that cuts deep into flesh and causes heavy bleeding. If prey is not killed with a suffocating neck hold, it is likely to die of blood loss, as the mordax will continuously re-adjust its devastatingly violent bite and dig in new, deep cuts each time it does so. 

The mordax has another edge over burdles and skuorcs in its sociality: it usually lives and hunts as a mated pair. When one bites onto a prey animal, the other can let go and re-adjust its own bite, and so on and on until the prey is debilitated and brought down. A single cub is born once every two years and stays at a safe den with its mother's full attention for its first month, while the male brings them whatever food he can acquire on his own. Once a little older, it will begin to leave the den on its parents back for longer forays, but will not be strong enough to help hunt until it is at least a year old, and so must be left behind during hunts requiring both adults combined strength to succeed.