Suskityrannus

Suskityrannus (name meaning "coyote tyrant"), referred to as "Zunityrannus" (meaning "Zuni tyrant") in the series, is a genus of tyrannosauroid theropod dinosaur that lived in North America during the Late Cretaceous period.

The Great Survivors
A lone Suskityrannus is first seen drinking from a lake. It then came across a Nothronychus and attempted to attack the herbivore. However, the therizinosaur swiped its claws at the tyrannosaur's face and successfully warded it off. The Suskityrannus then turned its attention to a carcass. Unbeknownst to the tyrannosaur, the carcass contained the deadly pathogenic bacteria Clostridium botulinum, and later died from it. The Nothronychus then returned to eating.

Later, a larger pack of Suskityrannus appeared and walked past a dead individual. They then started hunting a pair of Nothronychus. However, using their enormous claws, the therizinosaurs were able to defend themselves. Despite this, one Suskityrannus' managed to bite one of the herbivores' necks. The pack then backed down and began to cannibalize on the dead tyrannosaur, not being aware that it also contained the deadly pathogen. The theropods then contracted the bacteria and died as well, as was later seen when a Nothronychus walked past and saw their rotting bodies near the lake.

Trivia

 * At the time of Planet Dinosaur's airing, Suskityrannus had not been officially described yet, so it was referred to as "Zunityrannus", which means "Zuni tyrant". This informal name refers to the Zuni Basin in New Mexico, where fossils of the animal have been found. The remains of the animal wouldn't be formally described until 2019.
 * In the subtitles of The Great Survivors, Suskityrannus (then undescribed at the time) is inaccurately referred to as Sinotyrannus,​​​​​​ which was a large tyrannosaur from Early Cretaceous China, over 28 million years earlier than Suskityrannus.