The 'Rocky Lizard King' of Skull Island is one of the few living dinosaur descendants on the island. The Lithosaurus Rex is a descendant of tyrannosaurid theropods, believed to most likely be living descendants of Tarbosaurus due to Skull Islands geographical location and close proximity to Asia. Lithosaurus Rex are the main predator of the Lithoceratops and have evolved several very unique adaptations to hunt them. Their forearms have become large and work to dig to find Lithoceratops in hibernation. When encountering live Lithoceratops, they use their highly modified skulls that due to convergent evolution, function similar to pachycephalosaurid dinosaurs. These skulls turn Lithosaurus Rex into living battering rams able to shatter stone and diamond. Highly modified ossified tissue around the mouth and teeth evolved to crack and chew through stone to get into the soft tissue of Lithoceratops. Their guts also contain Lithotrophic bacteria allowing the Lithosaurus Rex to digest the inorganic stone of Lithoceratops armor.
Lithosaurus rex has been suggested to play 6 roles. Click below to see other actors suggested for each role, and vote for who you think would play the role best.