Science Correspondent Sue Nelson: More to two-legged dinosaurs than the origin of birds

It had curved claws like giant meathooks, measured 36ft (11m) from head to tail and had a long, narrow crocodile-like skull that probably helped it catch fish.

This is Suchomimus tenerensis, fossilised bones of which have just been dug up in the central African state of Niger.

Lead palaeontologist Paul Sereno and his team in Africa

It stalked the Earth about 100 million years ago in the middle of the Cretaceous period, when the face of the Earth was very different from today - the break-up of the supercontinent had begun relatively recently.

The new dinosaur was one of the theropods - two-legged carnivores whose ranks ranged in size from chicken-sized dinosaurs weighing only a few kilos to the fearsome Tyrannosaurus rex, weighing six tonnes.

The long narrow jaws of this new creature suggest that it had adapted to eat fish. Its teeth are pointy and conical which would have been good for grasping and piercing. Other theropods have blade-like teeth.

Exposed fossils

The excavation was led by Paul Sereno of the University of Chicago and is reported in the journal Science.

Professor Paul Sereno: It was an accidental find.

"The thumb claw and a few of the bones were actually exposed and lying on the surface - almost begging us to dig further and find out whether there was more of the animal there," he said.

"It only became clear after about a week of excavation."

It is an important find. Suchomimus tenerensis is believed to be the missing link between two other fish-eating dinosaurs. One of these, the Baryonex, was found in the UK, in Surrey, 15 years ago, with partly digested fish in its stomach.

The locations of these different discoveries should tell us more about the distribution and break-up of ancient land masses, as well as shedding new light on dinosaur evolution.

Huge claws

Postgraduate Oliver Rauhut, from the UK's Bristol University, was part of the team that uncovered the dinosaur last December.

"This is an interesting find because it belongs to a group of dinosaurs that are very poorly known," he said.

"Also, it's an African dinosaur, and that's the least known continent in terms of dinosaur evolution.

"We don't really know how it lived, but the suggestion is that it ate fish, which is very possible.

"It could be that it dredged up small prey - that is, small for a creature 11m long. The fish it hunted might have been up to five metres in length."

But Mr Rauhut said the dinosaur's huge claws and powerful front limbs suggested that it may have eaten terrestrial prey as well.

"The largest claw we found measured 14 inches [35.5cm] along the outer curve," he said.