This animal (Carcharodontosaurus) makes you wonder how evolution could have stood still for so long. It was a real survivor.

Thirty years ago, when Paul Sereno was only fifteen and probably more interested in girls than reptiles, French paleontologists had discovered several skulls and various bones of what appeared to be a giant crocodile. Naming the find Sarcosuchus imperator, (flesh eating crocodile), the french left the skeleton and the research alone and it remained so until 1997, when University of Chicago Professor and now grown paleontologist, Paul Sereno resumed excavations in Niger, in the Sahara.

Sereno, also an explorer-in-residence at the National Geographic Society, was no rookie; Working in the field since 1988, this Columbia graduate, had previously discovered new dinosaur species on several continents. First in 1988, in the Andes of Argentina, his team unearthed Herrerasaurus, the first complete skeleton of this primitive dinosaur. In the same area, in '91, Sereno and his team, which often included his students and his wife, discovered a small skeleton which would date back 228 million years, known as Eoraptor, a new species.

His first trip to Niger in '97 proved eventful, when Afrovenator, a 27-foot-long predator was discovered. Next excavated were two skeletons from the 60-foot-long herbivore, Jobaria tiguidensis and a 36-foot-long fish-eating predator, Suchominus. Then in Morroco in '95, a skull from the Cretaceous period was found, which belonged to the genus, Carcharodontosaurus, a huge meat-eater (How one ascertains the diet of 100 million year old creatures is a mystery to me, and certainly beyond the scope of this writeup). And so now we return to 1997, and Sereno's resumption of the giant croc mystery, as it came to be known.

We had never seen anything like it, Sereno said, The snout and teeth were designed for grabbing prey-fish, turtles, and dinosaurs that strayed too close.

In expeditions that lasted until the year 2000, skulls, vertebrae, limb bones, and foot-long bony armor plates called scutes were found. Analysis has shown that Sarcosuchus lived approximately 110 million years ago, give or take a year or two, and could have been as long as 40 feet and weighed 17,500 pounds. It's 100 tooth, six-foot long jaws may well have consumed small dinosaurs. It remains the most complete crocodilian speciman found to date.

Sereno and his wife, Gabrielle Lyon, co-founded Project Exploration which takes kids out of the classroom and into the field and brings dinosaur and science discoveries to the public.