By Shaun Smillie
The Free State highveld contains the remains of a prehistoric oasis where mysterious animals once roamed, including a shadowy meat-eater known simply as Carnivore X.
Yesterday, one of these animals was revealed at the Wits Origins Centre in Joburg. The new species is a plant-eating dinosaur, which has been given the name Aardonyx celestea.
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The Aardonyx was at least 7 metres long, and could look a man in the eye when it was not yet fully grown.
Dr Adam Yates, of Wits University's Barnard Price Institute, and his team found the two skeletons of Aardonyx near Senekal in the northern Free State.
Their findings have been published in the Proceedings of the Royal Society journal, after five years of working on the new discovery.
"Aardonyx probably walked on its hind legs, but could drop on all fours as well," said Yates.
The dinosaurs were found at a site called Marc's Quarry. Yates believes that 195 million years ago, this was an oasis, teeming with life.
"It was probably a well-watered area in a dry floodplain," explained Yates. In this oasis, he believes, were huge rhino-sized herbivores, very different to the dinosaurs which lived in areas that were just kilometres away.
"To feed such animals you would need to have had quite a large volume of plants," he said.
But with the lush vegetation and giant herbivores would have come a big carnivore, to fill a niche in the food chain. This carnivore has left clues of its existence, with several 10cm-long teeth that were found among the bones of the two Aardonyx.
"When we first found them, we thought they were claws, but then we noticed the serrated edges and we knew they were teeth," Yates explained.
Dinosaurs, he said, shed their teeth on a regular basis, often when they were feeding, and would then grow new ones.
How big was Carnivore X? Yates can only guess: "Probably seven to eight metres in length, about the size of a small T Rex, which is huge for this period."
But Carnivore X is not the only inhabitant of this early Jurassic oasis - Yates and his team have found two other new species of herbivore, which they are currently in the process of naming.
"What this is showing is that these dinosaurs were not widely distributed. They had narrow ecological preferences," said Yates.
While the site that yielded Aardonyx has been emptied of its fossils, there is another bone field that the team want to explore in the hope that this will reveal more of the mystery oasis.