Unearthed bones prove 'super-croc' was as big as a bus

It not only walked with dinosaurs, it ate them as well. The bones of an extinct species of crocodile that grew to the length of a London bus, weighed as much as a small whale and was armed with a set of 6ft jaws has been unearthed from an African desert.

It not only walked with dinosaurs, it ate them as well. The bones of an extinct species of crocodile that grew to the length of a London bus, weighed as much as a small whale and was armed with a set of 6ft jaws has been unearthed from an African desert.

So enormous was this "super-croc", scientists believe it would have had no problem tackling dinosaurs that lived with it in an ancient swamp some 110 million years ago.

The latest fossilised bones to be dug out of the Tenere Desert of Niger in West Africa suggest that the supercrocodile grew up to 40ft long, weighed more than eight tons and lived for about 60 years.

Although a partial skull of the species, named Sarchosuchus imperator or "flesh crocodile emperor", was first discovered in 1964, the latest specimens reveal the true nature of the beast – the biggest crocodilian reptile discovered to date.

Paul Sereno, a renowned dinosaur specialist at the University of Chicago, led the team which yesterday published a description of the most complete skeleton of the crocodile in the journal Science.

"This new material gives us a good look at hyper-giant crocodiles. There's been rampant speculation about what they looked like and where they fit in the croc family tree, but no one had enough of the skull and skeleton to really nail any of the true croc giants down until now," Dr Sereno said.

Although the site of the find now bakes in temperatures of 65C, it was once a wet, warm area similar to Florida, where giant crocodiles competed with equally large meat-eating dinosaurs for prey comprising of 20ft sauropods – long-necked vegetarian dinosaurs.

Sarchosuchus had a jaw studded with about 100 "stout, smooth and rounded" teeth for puncturing and crushing. The upper jaw overhung the lower jaw by several inches, suggesting the creature attacked large prey in a death grip, similar to the killing method favoured by crocodiles today.

"A small sauropod, 20 or 30 feet in length, would have been no problem. Once one of these [jaws] clamped onto the leg or neck of an animal, there wasn't a lot it could do," Dr Sereno said.

One of the distinguishing features of the species was that it was covered from head to mid-tail in overlapping bony plates, called scutes, embedded in the skin, which evidently acted as body armour.

The annual growth rings of the scutes analysed by the scientists suggest that Sarchosuchus took between 50 and 60 years to reach full size. This is surprisingly long-lived for a crocodile, they said.

Eye sockets in the skull point upwards and suggest that the animal lurked submerged for long periods while watching the shoreline. "This suggests it was an ambush predator, hiding under the water and then surging out to grab anything lounging on the shore," he said.

A large growth at the end of the snout has proved more difficult to explain. "Crocodilians are among the most vocal reptiles, so I wouldn't doubt that it may have been involved in both sound and smell," he said.

The scientists have unearthed six different crocodile species from the same period, suggesting it was a rich time for the reptilian group. Some "bite-sized" species grew no bigger than a terrapin, Dr Sereno said.

"That's the fascinating thing about crocodile evolution. It seems like modern crocodiles have been trimmed at each end of their size range, with the little ones and the big ones disappearing,"he said.