As if average-sized crocodiles aren't terrifying enough, a team of researchers recently discovered an ancient relative of the reptile that was roughly the size of a bus, with a skull over five feet long.

According to BBC, the 30-foot creature lived 130 million years ago during the early Cretaceous period and has been given the name Machimosaurus rex ("fighting lizard-king") for its impressive size. At the time, it was the largest known marine crocodylomorph, a group of extinct animals that includes crocodilians and their relatives. "There's no question this animal had a terrific diet," co-discoverer Federico Fanti said of the remains, which he and his team found while exploring a part of Tunisia where no one had searched for fossils before. The bones were visible without digging, Fanti said. "We could see the outline of the body in the ground and counted more than one."

The researchers say that the discovery of Machimosaurus rex could change scientific understanding of the transition between the Jurassic and the Cretaceous periods. While some scientists believe a mass extinction event occurred during the transition, the fact that Machimosaurus rex seems to have survived about 20 million years past the extinction of other large reptiles undermines the mass die-out theory.

"We think that we are not looking at a global extinction but local extinction of different species," Fanti told BBC. "Dependent on where in the world you are digging, you are going to find that some species survived and others did not."

The researchers' report on the discovery, published in the journal Cretaceous Research, includes a graphic showing the size of the newly discovered species in comparison to an adult human. 

[h/t: BBC]