Monster croc probably ate large dinosaurs

WASHINGTON -- Watchful and still, a monster crocodile waited in the waters of an African river for a large animal to lean over and drink. When the moment was right, the predator lashed out and grabbed the prey in his toothy jaws. The struggle was brief.

That's a scene researchers believe was routine in a lush river valley some 110 million years ago. The prey could have been a large dinosaur, but the crocodile was immense -- longer than a school bus and weighing about 10 tons.

Dinosaur hunters led by Paul C. Sereno of the University of Chicago uncovered fossilized remains of the giant croc and for the first time assembled them into a replica of the ancient reptile.

"When this thing grew into an adult it was really a monster," Sereno said in an interview. "This thing could have easily pulled down a good-sized dinosaur."

The fossils were found last year in what is now a desert in Niger. In the age of the dinosaurs, the location was a verdant river valley, alive with dinosaurs and at least five types of crocodiles, including a monster species called Sarcosuchus imperator, or "flesh crocodile emperor."

Sarcosuchus was first discovered by French scientists in 1964, but the Sereno find is the most complete fossil skeleton known.

"This new material gives us a good look at hyper giant crocodiles," said Sereno in a statement. "No one had enough of the skull and skeleton to really nail any of the true croc giants until now."

Ambush predator

Sereno said that the elongated skull of the Sarcosuchus (pronounced SARK-oh-SOOK-us) is about six feet in length and dominated by narrow jaws studded with more than 100 teeth. The upper jaw, tipped with large, sharp and powerful incisors, overlaps the lower jaw, an ideal design to lock and hold onto flesh.

"The teeth are incredibly stout," he said. "They are crushing, penetrating teeth," which means the animal probably fed on land animals more than on fish and turtles, the most common food of modern crocodiles and alligators.

Sereno said the animal's eye sockets are rotated upward, enabling it to remain submerged in water 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.

Modern crocodiles living in African rivers often grab large animals, such as wildebeest and zebras, and drag them into the water where they are drowned and then torn apart.

Sarcosuchus probably did the same thing, said Sereno, but because the ancient animal was so large, it could easily handle huge dinosaurs, including the massive long-necked, small-headed sauro-pods that were common in that African region.

"A small sauropod, 20 or 30 feet in length, would have been no problem," said Sereno. He said the giant crock probably remained still in the water until an animal came to drink and then it whipped its jaws out and sunk its teeth into its prey.

"And that would have been it," Sereno.

Michael Parrish, chairman of biology at Northern Illinois University and a noted dinosaur researcher, called the Sereno discovery "an important find."

Sarcosuchus was already known, said Parrish, "but this is a much more complete skeleton" and proves how big the animal was.

"A lot of people have not appreciated how big these crocodiles got," he said.