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SuperCroc Rocks!

We had never seen anything like it. With brushes and awls we teased away the rock encasing its fossilized jaws. Yet the animal that had once wielded these jaws was not a dinosaur. It was a colossal crocodilian.

Image: Crocodilian attacking a dinosaur
SuperCroc (Sarcosuchus imperator) vs. Suchomimus tenerensis
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We had come to hunt dinosaur bones in the Sahara's legendary fossil graveyard, a remote windswept stretch of rock and dunes called Gadoufaoua. In Tamashek, the language of the desert's Tuareg people, Gadoufaoua means "the place where camels fear to tread." For fossil hunters it means paradise—the richest dinosaur beds on the African continent. Now less than an hour into our four-month expedition we were face-to-face with an ancient croc that could have posed a serious threat to any dinosaur within reach.

This croc wasn't new to science. Some of its conical teeth, vertebrae, and foot-long (0.3-meter-long) armor plates, or scutes, were first discovered by French paleontologist Albert-Félix de Lapparent. In 1966 his niece France de Broin and fellow paleontologist Philippe Taquet named the creature Sarcosuchus imperator, the "flesh crocodile emperor."

We called it SuperCroc. And we were hoping to answer some lingering questions about this little-described giant.

Expedition 2000, funded in part by the Society's Expeditions council and its Committee for Research and Exploration, was my fourth to the Sahara, and it was no holiday in the sand. We had to transport trucks, tools, tents, five tons of plaster, 600 pounds (270 kilograms) of pasta, 4,000 gallons (15,000 liters) of water, and four months' worth of other supplies into the heart of the world's largest desert. Truck-engulfing sand, a trucker strike, and gas shortages cost precious time. But when, on August 30, we finally reached the first of our four camp locations, we struck it fossil rich from the start.

"The backbone!" shouted David Blackburn, a student from the University of Chicago. Trenching around a large Sarcosuchus skull, he discovered a series of vertebrae snaking into sediments laid down by a river some 110 million years ago. Undeterred by the blistering heat, he and other members of my 16-person crew were closing in on beautifully preserved pieces of SuperCroc's skeleton.

"Gorgeous armor," mused paleontologist Hans Larsson, examining a stack of foot-long (0.3-meter-long) bony scutes that looked like roofing tiles. These would have provided an impermeable shield over SuperCroc's neck, back, and tail. Throughout their evolution all crocs have sported this body armor. It's SuperCroc's skull that's unparalleled.

More than a hundred teeth jut from narrow jaws that must have been adept at snagging fish. And unlike any other croc, living or extinct, SuperCroc's skull gets wider toward the front end, which is armed with a deadly row of enlarged incisors. These robust bone-crushers suggest that Sarcosuchus could eat far meatier prey than fish.

The swollen end of the snout houses an enormous cavity under the nostrils, meaning this croc may have had an enhanced sense of smell and a most unusual call. Its eye sockets project upward—like those of the living gharial in India—for scanning the river's edge while submerged. SuperCroc's skull, then, is like a cross between the elongate skull of a fish-eating gharial and the robust skull of a bloodthirsty Nile crocodile.

With the discovery on this expedition of several skulls, vertebrae, scutes, limb bones, and other assorted bits, we have amassed about 50 percent of SuperCroc's skeleton, enough to commission a life-size model. Our most complete skull is just shy of six feet (two meters). After measuring the bones and comparing them with those of modern crocs, we estimate that a mature adult Sarcosuchus grew to about 40 feet (12 meters) long. Its weight? As much as ten tons. Among the very largest crocs that ever lived, Sarcosuchus sprouted from a side branch of the crocodilian family tree separate from that leading to modern crocodiles.

Dwarf crocs we discovered living alongside Sarcosuchus represent other lineages that have come and gone. Extinction has trimmed the largest and smallest of the croc family. Yet unlike dinosaurs, crocs today are much as they were more than a hundred million years ago—masters at ambushing prey and one of Earth's most persistent survivors.

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