This new member of the fish-eating spinosaurid family, whose long, narrow skull looks even more like a crocodile than the other known spinosaurids, would have been some 11 meters (36 feet) long and weighed five tonnes. The initial discovery in the desert of a 30-centimeter (12-inch) sickle-shaped thumb claw resembling a meat hook was made almost by chance.

``It was lying on the surface of the desert, completely exposed by wind and sand and would have been visible like that for centuries to anyone who walked by,'' Sereno said. Digging in the surrounding area, the paleontologists found some 400 pieces of the fossil, making it the most compete spinosaurid specimen ever discovered.

Like the other known spinosaurids, it had a long, narrow snout with impressive claws at the end of its small forelegs. But its skull was markedly different. ``It's a new kind of spinosaur,'' Thomas Holtz of the University of Maryland at College Park said. ``The skull of this dinosaur looks much more like a crocodile snout than a typical meat-eating dinosaur snout.'' This characteristic convinced Sereno that he was looking at a new genus and species of dinosaur he named Suchomimus tenerensis, or the crocodile of the Tenere desert.

Holtz says that the crocodile-like features -- a long snout that allowed smoother passage through water and pointed teeth that pierced and grasped rather than sliced -- would help scientists refine the family tree of the two-legged dinosaurs. ``This suggests a shift from a typical meat-eater which would just eat terrestrial animals to one that's going after large fish,'' he said. ``This very long snout enabled them to grab a fish and hold on to it very tightly as the fish struggled. They got most of their food by catching fish in water, but because they are land-living animals they can go from stream to stream.''

This means that the Suchomimus would have lived like Alaska's grizzly bear does today, eating mainly fish but using its ability to move on land to fish across a large area. The discovery also changes prevailing views of how this family of dinosaurs migrated across the enormous landmass of Pangaea, the single Earth continent which existed when they roamed the Earth.

Until this find, only one specimen similar to the Suchomimus had been discovered in Britain and two other, more primitive fossils had been unearthed in Egypt and Brazil. The discovery of a more developed dinosaur in the southern hemisphere -- which the scientists believe must have come from the North -- indicates that these animals must have continued to migrate across a land bridge even after the Tethys Seaway formed between what would later become the continents of the northern and southern hemispheres.

-- Agence France Presse