The giant croc that could dine on a dinosaur

Scientists have come up with a remarkable new monster just in time for Hallowe'en, a giant crocodile big enough to gobble up a dinosaur.

Massive is hardly a big enough word to describe the stunning Sarcosuchus imperator, dug out of the ground in Niger by Dr Paul C. Sereno of the University of Chicago and colleagues. Their find is described this morning in the journal Science.

This was no ordinary croc. It grew to at least 11 or 12 metres, about 40 feet in the old measure, and weighed in at eight tonnes, about as much as a small whale.

In life it was covered from head to mid-tail in an overlapping armour of bony plates embedded in its skin. Its long jaws made up about 75 per cent of the monster's head and a full-grown human could easily have reclined in the lower jaw with room to spare (but probably not for long).

Similar but smaller giant crocs have been found along the edges of former salt seas but Sarcosuchus lived inland and made its home in freshwater rivers, the researchers believe.

This finding may in part explain the beast's teeth, which came in for special analysis by the Chicago group.

The giant's lower teeth fitted inside the upper teeth rows during a bite, rather than interlocking like the teeth of an exclusively fish-feeding jaw.

They were stout, smooth and rounded and highly suited for puncturing and crushing, says Dr Sereno, who believes that small or juvenil dinosaurs off for a quick drink at the river were on Sarcosuchus's menu.

"The giant crocodilian Sarcosuchus stands in sharp contrast to its closest of kin, its jaws and teeth those of a generalist predator unearthed from fluvial deposits within a terrestrial setting," the authors write.

French geologists in the TΘnΘrΘ Desert in Niger first discovered fossils of Sarcosuchus in 1964, but few conclusions could be drawn from the limited material found until now.

Dr Sereno's group changed all that with newly discovered fossil skulls and partial skeletons of this 110-million-year-old giant. "This new material gives us a good look at hyper giant crocodiles," he says.

They were able to estimate age by counting the annual growth rings found in the bony skin plates. Some gave ages at death of 40 years but the researchers believe they lived longer. "This count suggests that maximum adult size was achieved only after a duration of 50-60 years."