Fossil dinosaur tracks left by huge ancient predator in Africa

A trail of fossilizedthree-toed footprints that measure nearly 57 centimetres (two feet)longshows that a huge meat-eating dinosaur stalked southern Africa200 million years ago at a time when most carnivorous dinosaurswere modest-sized beasts.

Scientists on Thursday described the footprints from anancient river bank in Lesotho, and estimated that the dinosaur,
which they named Kayentapus ambrokholohali, was about ninemetres (30 feet)long.

No fossilized bones were found, but the footprints aloneshowed a lot about the animal. The scientists concluded it was alarge theropod the two-legged carnivorous dinosaur group thatincluded later giants like Tyrannosaurus and Giganotosaurus but that it was more lightly built than those brutes. Thetheropod group also gave rise to birds.

Kayentapus lived early in the Jurassic Period, shortly aftera mass extinction that doomed other large reptilian terrestrial
predators that lived in the preceding Triassic Period, whendinosaurs first appeared.

"Our finding corroborates the hypothesis that theropodsreached a great size relatively early in the course of their
evolution, but apparently not before the Triassic-Jurassic boundary," said paleontologist Fabien Knoll, of the Dinopolis
Foundation in Spain and the University of Manchester in Britain.

No bones

There are no skeletal fossils of meat-eating dinosaurs thislarge so early in the dinosaur evolutionary history. It lived on
the ancient southern hemisphere super-continent of Gondwana.

There are other fossilized footprints from Poland thatindicate a similar-sized theropod inhabited the northern
super-continent of Laurasia around the same time.

Theropods of similar size do not appear in the fossil recorduntil 30 million years later, Knoll said.

The footprints were found on what was once a river bank,bearing telltale ripple marks and desiccation cracks.

"It is the first evidence of an extremely large meat-eatinganimal roaming a landscape otherwise dominated by a variety ofherbivorous, omnivorous and much-smaller carnivorous dinosaurs,"added paleontologist Lara Sciscio of the University of Cape Townin South Africa.

The research was published on Wednesday in the journal PLOSONE.

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