The Tyrannosaurus rex may have been a gigantic and terrifying creature feared by its preys millions of years ago but it is not the biggest predatory dinosaur to walk the Earth during the prehistoric era. A swimming dinosaur was.

Scientists believe that a carnivorous dinosaur called Spinosaurus aegyptiacus, a gigantic creature measuring 50 feet that lived in North Africa 95 million years ago is potentially the biggest meat-eating dinosaur that existed.

Remains of the dinosaur were first found by German paleontologist Ernst Freiherr Stromer von Reichenbach a little over a hundred years ago in Egypt but these were destroyed when a bomb hit and destroyed the museum that housed the fossils during World War II. A new fossil brought by a nomad to Nizart Ibrahim, a paleontologist with the University of Chicago's Organismal Biology and Anatomy, now gives scientists a second chance at taking a better look at the dinosaur.

After reconstructing the skeleton of the Spinosaurus aegyptiacus based on the newly found remains of the animal that were dug from eastern Morocco's Kem Kem beds, Ibrahim and colleagues, who described their findings in a study published in the journal Science on Sept. 11, confirmed that the animal was over 49 feet long, or at least 8 feet longer compared to the T-rex. The skeleton, however, suggests that the animal was still growing so scientists believe that a fully-grown adult would have been bigger.

The researchers also found evidence that the Spinosaurus was a good swimmer. Although scientists have long believed that the creature can swim, the new specimen provided evidence of the semi-aquatic lifestyle of the animal. Ibrahim and colleagues determined that the dinosaur had an array of adaptions that gave it the ability to spend much of its time in the water.

"Unlike terrestrial theropods, the pelvic girdle is downsized, the hind limbs are short, and all of the limb bones are solid without an open medullary cavity, for buoyancy control in water," the researchers wrote. "The short, robust femur with hypertrophied flexor attachment and the low, flat-bottomed pedal claws are consistent with aquatic foot-propelled locomotion."

The fish-eating dinosaur had another distinct characteristic in that it has four legs while all other meat-eating dinosaurs had two legs. Scientists also believe that the giant creature did not walk gracefully in land albeit it would have been a fearsome animal.

"It would have moved in a really freaky, weird way in comparison with its relatives - whether on land or in water," commented Paul Barrett, from London's Natural History Museum.