Palaeosaniwa was an extinct genus of carnivorous lizard from the late Cretaceous of North America. The name, given by Charles Whitney Gilmore in 1928, means "ancient Saniwa from Canada", Saniwa being another extinct genus of monitor lizard.

Measuring around 3–3.5 m (9.8–11.5 ft) in length, it was among the largest terrestrial lizards known from the Mesozoic period (though Asprosaurus may compete with it in size).

Palaeosaniwa's teeth were sharp and flattened like blades, with small serrations along the edges, indicating it was a carnivore. Palaeosaniwa fed on small vertebrates, including mammals and other reptiles, like small dinosaurs including the young of larger species. Palaeosaniwa itself was likely prey to the predatory dinosaurs it shared its habitat with.

Palaeosaniwa is a member of Platynota, a group that includes the monitor lizards (Varanidae) and Gila monsters (Helodermatidae) which could mean it might have had venom similar to that of a Komodo dragon or Gila monster. Originally, it was thought to be a member of the Varanidae, but has also been interpreted as a relative of the Helodermatidae. The most recent analysis places Palaeosaniwa outside of either Varanidae or Helodermatidae, as a stem member of the Varanoidea, although still under debate.

In SaurianEdit

Palaeosaniwa is one threat to the player while they are young, as its diet included young or small dinosaurs. It is portrayed looking very similar to a Gila monster, with thick, warty scales and a black and bright orange color palette. It is able to sprint a little bit, and buffs the player with intimidating sounds. If the player gets bitten by this lizard, the former will contain the venom of the latter, which can lead to the player's death, if it isn't careful. Palaeosaniwa will likely charge and try to kill the player when young, but will prefer buffing the player if it is an adult, avoiding attacks.