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UCT palaeontologists open cold cases

2 May 2014 - 09:15

The fossils of pre-historic animals, often found in bits and pieces, are jigsaw puzzles that have to be pieced together, calling for lots of study and deductive reasoning.

Nick Fordyce with Prof Anusuya Chinsamy-Turan Dicynodont
Bone collectors: Nick Fordyce with Prof Anusuya Chinsamy-Turan have made some eye-catching discoveries about some of South Africa's prehistoric creatures. Murder site: A picture of a dicynodont's final resting place, its bones and associated remains providing clues to its death.

Palaeontologists in UCT's new Department of Biological Sciences have recently been applying their sleuthing skills to two fossils dating back hundreds of millions of years. In the first of two studies, published online in the US-based Journal of Vertebrate Palaeontology, honours student Tobias Nasterlack, working with postdoctoral research fellow Aurore Canoville and palaeobiologist and head of department Professor Anusuya Chinsamy-Turan, picked and prodded at the skeletal remains of a toothless mammal-like reptile known as Cistecephalus.

In so doing, the team hoped to glimpse insights into the lifestyle habits of the 40cm-long creatures, which lived 255 million years ago in the area now known as the Karoo. Was it, as has been debated, aquatic, amphibious, a tree climber or, the more popular theory, a burrower?

"Bone microstructure is a powerful tool that enables deductions about the lifestyle of extinct animals," explains Canoville.

What they have been able to glean from the adults' thick-walled bones, for example, is that it is similar to that of many digging animals of today, suggesting that Cistecephalus was not a tree climber but rather a burrower.

In a second study, published in the South African Journal of Science, honours student Nicholas Fordyce, working with Chinsamy-Turan and Roger Smith of the Iziko South Africa Museum, has cast a light on a 253-million-year-old murder mystery. His research pointed the finger for the killing of a plant-eating reptile known as a dicynodont - specifically one named Mamafura, whose partial skeleton was discovered in 1984 - to a suitably vicious-looking carnivore known as Aelurognathus.

The researchers came to this conclusion based on the smoking gun found near the scene of the crime, namely a 3.5cm long, sharply pointed, curved and serrated carnivore canine. In the defence of the Aelurognathus, other forensic evidence - notably the belly-up posture of the skeleton and the mudrock around it - would suggest that the Aelurognathus had merely come across Mamafura's carcass after it had drowned, and opportunistically fed on it, losing the tooth in the process.

"Fossils provide us with a unique opportunity to learn about how the world and its fauna and flora have changed through time," says Fordyce.