The animal in question is thought to be Carcharodontosaurus, its corpse was being scavenged by a Spinosaurus which lost a tooth in the process. It's possible that Spinosaurus was a “carrion pirate”, stealing carcasses from other predators by using its large size for intimidation, similar to how lions and bears scaring away cheetahs and wolves from their kills. The only animal there is definitive evidence of Spinosaurus hunting is the 1 ton sawnosed skate, Onchopristis. A fish vertabrate was found in the tooth socket of a Spinosaurus jaw back in 2008. It wasn't an easy target however, Onchopristis was just as dangerous as the dinosaurs.