Razana ruled Madagascar around 165 million years ago, back when the island was breaking off from Africa. The massive animal had serrated teeth, perfect for cutting into flesh. In fact, the serrations on the Razana's teeth are larger and more densely packed than on a T. rex's. The Razana likely preferred eating sauropods—tall, long-necked, big-bodied herbivores. But the croc wasn't the only meat-eater on the island. It co-existed with fellow carnivores from the dinosaur theropod family, bipedal animals with small arms and long tails for balancing. (The T. rex is a member of this family, but the Razana came before by approximately 100 million years.) For the most part, Razana didn't have many rivals on Madagascar, says Dal Sasso.