The 250-million-year-old galesaurus on Annelise Crean’s workbench at the South African Museum is a superbly prepared fossil, its tracery of delicate off-white bones standing out from a matrix of fine grey sandstone.
But where the dusty eye sockets should be, there is a surprise: the creature has protuberant, glistening and definitely not prehistoric brown eyeballs.
Crean laughs, explaining that the eyeballs are glass, borrowed from the museum’s taxidermy section.
”That’s just to give it a bit of life,” she says. ”The empty eye sockets look kind of dull and lifeless.”
She adds after a moment: ”His name’s Eugene.”
Crean can be forgiven the idiosyncrasy. She has already spent two months working on the 50cm-long, weasel-like reptile, found by her museum colleague, palaeontologist Roger Smith, near Bethulie in the Free State.
Eugene arrived on her desk as a lump of sandstone with only an exposed patch of weathered bone — his nose — giving a clue to the riches inside.
And it will probably take several more weeks of painstaking labour before Crean is satisfied with the result — if the nodule sticking out of the rock below Eugene, which she has not yet explored, doesn’t prove to contain another fossil.
One of a handful
Crean is a fossil preparator, one of only a handful in South Africa of a breed whose mind-boggling patience and skill allow scientists to unravel the mysteries of some of the earliest forms of life on the planet.
Her days are spent peering through a binocular microscope as she exposes the anatomy of creatures that walked the earth 50-million years before the dinosaurs. She uses tools such as an air scribe — best described as a miniature jackhammer with a tungsten carbide tip, a dentist’s drill, a needle-thin probe and water-colour paintbrushes.
Knowing that researchers will be interested in even the minutest details of the bone surface, she works with extraordinary care.
The air scribe knocks off pieces of rock little larger than a good-sized flake of dandruff. The drill allows even finer work, and with the probe she will remove a few grains at a time.
”You’ve got to have a steady hand and lots of patience,” she says. ”You gain knowledge as you go along. You learn the layout of the skeletons, where you would expect to find the bones, but you’ve got to be careful because they are often disarticulated, and you find bones where you don’t expect them.”
Eugene’s tail is a good example of disarticulation: a string of vertebrae from the midsection was missing, and Crean found them resting — still in perfect order — on a hind leg.
As she exposes bone, she coats it with Paraloid, an acetone-soluble fixative, to prevent it crumbling.
Answers to questions
Much of Crean’s work is for the museum’s displays, but the first priority with Eugene will be study by Smith and fellow palaeontologists who are champing at the bit to get their hands on the prepared galesaurus specimen.
”It’s unique: it’s the only one of its kind which is absolutely complete,” she says.
The galesaurus is an ancestor of the first mammals, and Smith believes Eugene could answer some important questions about ”proto-mammal” physiology, such as whether he had a diaphragm for breathing, and whether he was warm- or cold-blooded, or something in between.
In the 28 years Crean has been preparing specimens for the museum, there have been some jobs that stand out in her memory — such as the pristerognathus she nicknamed Butch.
”That took a year, and it drove me absolutely crazy. The matrix, the rock, was hard, the hardest rock in the Karoo. It was painstaking. It’s on display in the museum now: it’s a complete skull with skeleton. Beautiful specimen, but a nightmare.”
The earphones Crean wears on the job serve a dual function: they muffle the whine of the air scribe, and pipe in music — classical, indigenous Maori or North American Indian music, and some 1960s favourites.
While she works she thinks, about ”anything and everything”, she says. ”I turn my life around in my mind constantly.”
But this does not mean she loses focus on the task at hand.
”I’ve got to be fully aware of what I’m doing. It takes a lot of concentration. In fact, so much so that at times you find you’re barely breathing, because when you’re looking through a microscope the movement is magnified.”
Important job
Mike Raath, curator of collections at the Bernard Price Institute for Palaeontological Research in Johannesburg, says the work of preparators such as Crean is vitally important for science.
”I really can’t overemphasise the crucially important part that preparation plays,” he says. ”Without it, we as palaeontologists have nothing to work on.”
But he warns that preparation is the single biggest bottleneck in palaeontology.
His views are echoed by Smith, who is on record on the need for better funding for training and equipment for preparators.
Smith says it is cause for concern that of the 12 000 specimens in the South African Museum’s Karoo collections, only about 5 000 have been prepared enough for scientific investigation.
”Fossils are … no good to anybody unless they can be seen and studied,” he says. ”The palaeontological heritage of this country is only as good as its fossil preparators.” — Sapa