THEY’RE digging for dinosaurs in Dordrecht.
A Wits University team is currently excavating the bones of a dinosaur on a farm in the district after its discovery two years ago. The site is on an eroded area of Willow Kloof, the farm of Hannie and Nellie van Heerden, about 35 km north-east of the Eastern Cape town.
The Wits scientists have made several visits since the site was first located in 2014, collecting loose bones on the surface, and excavating parts of the assemblage (collection of bones) which they came back to this week.
Team leader Dr Blair McPhee said the creature was probably a melanorosaurus, a vegetarian dinosaur that walked the earth some 205 million years ago.
“This one would have been roughly the size of a cow, but obviously longer because it’s got that long saurian tail and neck.”
“It would probably have been seven or eight metres long.”
What the excavators are dealing with is a jumble of bones embedded in soft grey shale, rather than a complete skeleton. They have not found a skull, but McPhee is nevertheless pleased with what they have been able to recover.
“We’ve got most of an animal; we have a hind limb, most of the forelimb material, representative vertebrae from most of the sections of the back. It’s a nice find, especially for the Lower Elliot formation where associated stuff like this [bones grouped together] is very rare.”
On Tuesday, the team used a jackhammer to loosen surrounding rock.
They then wadded wet paper towels around the exposed pieces of bone, and finally covered the entire lump with layers of hessian dipped in plaster of Paris, to make a protective jacket.
They planned on Wednesday to use hammer and chisel to knock the lump loose from the underlying rock, and plaster jacket the underside as well.
The jacket will protect the fossil and stop it from crumbling to pieces on the trip back to Johannesburg where expert preparators at Wits will use magnifiers and a tool like a dentist’s drill to remove the rock matrix and free the bones.
The first bones of melanorosaurus were collected in the 1920s on the north slope of Thaba Nyama (Black Mountain) in the Transkei. The scientific name is derived from the Greek words melas (black), oros (mountain) and sauros (lizard). In English, it would be black mountain lizard.
The melanororsaurus is an early relative of the brontosaurus.
The Elliot Formation that McPhee referred to is a geological layer, named for the town Elliot where its typical red shales are particularly noticeable, that contains fossils of a range of dinosaurs. Dordrecht lies on a lower and earlier geological layer known as the Molteno Formation, which normally has no dinosaur remains, but is rich in plant fossils.