/ 13 November 2009

Earth Claw dinosaur rises again

Wind and rain scoured the fossils into dust. But a team of South African, Australian and American scientists got there in time.

The result — a new species of dinosaur called Aardonyx, or Earth Claw — was announced around the world this week.

The new type of dinosaur, a long-necked vegetarian giant, was found almost by mistake on a Free State game farm outside Senekal. For a start, fossils from the sevenmetre- long Earth Claw, after surviving 195-million years, had been exposed and ‘were in the process of being eaten away by erosion”, said Pretoria geologist Johann Neveling from the Council for Geoscience.

In addition: ‘I was reluctant to excavate because getting to the site is a real pain,” confessed Adam Yates from the Bernard Price Institute for Palaeontological Research.

‘We had to fill up the creek with stones and dirt to drive across. Every time it rained, this got flushed away. And we seemed to bring the rain,” said the Australian-born dinosaur researcher, who is based at Wits University. ‘At first I thought it was just another pile of common dinosaur bones,” Yates said.

Then Boksburg-born student Marc Blackbeard came along, needing an honours level project, and began digging. ‘On his very first dig, pretty much within the first few bones that got exposed, I realised that I’d been completely wrong about this site. It was something new and different, rare — unexpected, to say the least,” Yates said.

‘The rocks are full of fossil fragments. When the first skull bone came up, it was like ‘wow, at last, something that’s complete, that’s promising’. There was no ‘eureka!’ moment but moments of excitement and the slowly mounting realisation that we had something special here.”

It took many painstaking digs through the bone bed for Blackbeard to piece together the final moments of the juvenile giant, a bulk browser who shovelled down his plant food.

‘A lot happened to this dinosaur. It had been trampled after death,” Blackbeard said. ‘Maybe a flash flood washed the decomposing remains into a shallow channel. What was left was scavenged — there are marks on the bone that look like teethmarks and we found several large teeth from another carnivorous dinosaur nearby.”

These fossils are ‘part of our history”, he added. ‘This dinosaur gives us insight into what happened on the African continent and insight into evolution. It’s not just early man that evolved and moved out of Africa. Dinosaurs did too.”

Although some of the skeleton has turned to dust, enough of the delicate bones were recovered to fill in missing gaps in our knowledge of the early Jurassic time, when Africa was a very different place, connected to all the land masses of the world.

Anusuya Chinsamy-Turan, a dinosaur bone specialist from the University of Cape Town, showed that Earth Claw died as a teenager.

‘Not much is known about the early evolution of this type of dinosaur, a forerunner to the sauropods, which were the world’s biggest land-living animals. How did they come to be so big? When did they switch from two feet to four?” asked Chinsamy-Turan, author of the book Dinosaurs of Africa.

Biomechanics researcher Matthew Bonnan from Western Illinois University in the United States said the animal stood on two feet, but was probably also capable of walking on all fours.

The bones are at Wits University and will go on display in Pretoria’s Transvaal Museum early in 2010. A three-dimensional mounted skeleton is proposed for the planned dinosaur museum at the Golden Gate National Park in the Free State